阅读说明：本技术 一种氮极性面氮化镓共振隧穿二极管及其制作方法 (Nitrogen polar surface gallium nitride resonant tunneling diode and manufacturing method thereof ) 是由 薛军帅 李祖懋 吴冠霖 姚佳佳 孙志鹏 杨雪妍 张赫朋 刘芳 张进成 郝跃 于 2021-06-11 设计创作，主要内容包括：本发明公开了一种氮极性面氮化镓共振隧穿二极管及其制作方法,主要解决现有氮极性面氮化镓共振隧穿二极管材料生长极性控制难度大、位错密度高,器件自热效应及微分负阻效应稳定性和重复性退化问题。其自下而上包括金刚石衬底、SiN过渡层、GaN支撑层、n～+GaN集电极欧姆接触层、第一GaN隔离层、第一势垒层、GaN量子阱层、第二势垒层、第二GaN隔离层、n～+GaN发射极欧姆接触层和发射极电极,第一GaN隔离层两侧设有环形集电极电极,第一GaN隔离层到发射极电极的外部包裹有钝化层。本发明器件材料质量高,器件可靠性和稳定性高,能改善器件自热效应并降低器件剥离转移工艺难度,可用于高频太赫兹辐射源和高速数字电路。(The invention discloses a nitrogen polar surface gallium nitride resonance tunneling diode and a manufacturing method thereof, and mainly solves the problems that the existing nitrogen polar surface gallium nitride resonance tunneling diode material is large in control difficulty of growth polarity, high in dislocation density, and degraded in stability and repeatability of a self-heating effect and a differential negative resistance effect of a device. It comprises a diamond substrate, a SiN transition layer, a GaN supporting layer and n from bottom to top + GaN collector ohmic contact layer, first GaN isolating layer, first barrier layer, GaN quantum well layer, second barrier layer, second GaN isolating layer, n + GaN emitter ohmic contact layer and emitterAnd the two sides of the first GaN isolating layer are provided with annular collector electrodes, and the passivation layer wraps the first GaN isolating layer and the emitter electrodes. The device has high material quality, high reliability and stability, can improve the self-heating effect of the device and reduce the difficulty of the device peeling and transferring process, and can be used for high-frequency terahertz radiation sources and high-speed digital circuits.)

1. A GaN resonant tunneling diode with nitrogen polar surface comprises a substrate (1) and n⁺The GaN collector ohmic contact layer (4), the first GaN isolating layer (5), the first barrier layer (6), the GaN quantum well layer (7), the second barrier layer (8), the second GaN isolating layer (9), n⁺GaN projecting pole ohmic contact layer (10), projecting pole electrode (11), first GaN isolation layer (5) both sides are annular collector electrode (13), and first GaN isolation layer (5) form the cylinder platform to projecting pole electrode (11) sculpture, and the outside parcel of this cylinder mesa has passivation layer (12), its characterized in that:

the substrate (1) is made of diamond material;

n is⁺A GaN collector ohmic contact layer (4) and a substrate (1) anda GaN supporting layer (3) and a SiN transition layer (2) are arranged between the two layers for supporting n of the resonant tunneling diode⁺A GaN collector ohmic contact layer and a deposition substrate.

2. A resonant tunneling diode according to claim 1, wherein:

the SiN transition layer (2) is 50nm-200nm thick;

the GaN supporting layer (3) is 4-10 mu m thick;

the substrate (1) has a thickness of 40 μm to 60 μm.

3. The diode of claim 1, wherein:

n is⁺A GaN collector ohmic contact layer (4) and n⁺A GaN emitter ohmic contact layer (10) with a doping concentration of 5 × 10¹⁹cm^-3-1×10²⁰cm^-3The thickness is 100nm-300 nm;

the thickness of the first GaN isolating layer (5) and the second GaN isolating layer (9) is 4nm-8 nm;

the first barrier layer (6) and the second barrier layer (8) adopt any one of AlN, AlGaN and InAlN, and the thickness of the first barrier layer and the second barrier layer is 1nm-3 nm;

the GaN quantum well layer (7) is 1nm-3nm thick;

the passivation layer (12) is made of SiN material and Al₂O₃Material, HfO₂Any one of the materials.

4. A method for manufacturing a nitrogen polar surface gallium nitride resonant tunneling diode is characterized by comprising the following steps:

1) on a self-supporting gallium nitride epitaxial wafer, graphene, BN and MoS with the thickness of 2nm-5nm are grown by utilizing a chemical vapor deposition process₂Any one of the transfer layers;

2) sequentially growing a GaN or AlN nucleating layer with the thickness of 50nm-200nm and a GaN buffer layer with the thickness of 1000nm-3000nm on the transfer layer by using a metal organic chemical vapor deposition process;

3) by usingMolecular beam epitaxy method of growing n on buffer layer⁺A GaN emitter ohmic contact layer (10) with a thickness of 100nm-300nm and a doping concentration of 5 × 10¹⁹cm^-3-1×10²⁰cm^-3；

4) By molecular beam epitaxy method at n⁺A second GaN isolating layer (9) with the thickness of 4nm-8nm is grown on the GaN emitting electrode ohmic contact layer (10);

5) growing a second barrier layer (8) with the thickness of 1nm-3nm on the second GaN isolating layer (9) by adopting a molecular beam epitaxy method;

6) a GaN quantum well layer (7) with the thickness of 1nm-3nm is grown on the second barrier layer (8) by adopting a molecular beam epitaxy method;

7) growing a first barrier layer (6) with the thickness of 1nm-3nm on the GaN quantum well layer (7) by adopting a molecular beam epitaxy method;

8) growing a first GaN isolating layer (5) with the thickness of 4nm-8nm on the first barrier layer (6) by adopting a molecular beam epitaxy method;

9) growing n on the first GaN isolation layer (5) by molecular beam epitaxy⁺A GaN collector ohmic contact layer (4) with a thickness of 100nm-300nm and a doping concentration of 5 × 10¹⁹cm^-3-1×10²⁰cm^-3；

10) Using a metal organic chemical vapor deposition process at n⁺A GaN supporting layer (3) with the thickness of 4-10 mu m is deposited on the GaN collector ohmic contact layer;

11) depositing a SiN transition layer (2) with the thickness of 50nm-200nm on the GaN supporting layer (3) by using a low-pressure chemical vapor deposition technology;

12) depositing a diamond substrate (1) with the thickness of 40-60 mu m on the SiN transition layer (2) by using a microwave plasma chemical vapor deposition process;

13) stripping the self-supporting gallium nitride epitaxial wafer and the transfer layer;

14) removing the nucleating layer and the buffer layer by using an etching technology;

15) n is to be⁺The GaN emitting electrode ohmic contact layer (10) and the upper part of the GaN emitting electrode ohmic contact layer are integrally turned over up and down;

16) using conventional optical lithography, at n⁺GaN emitter ohmic contactForming a mesa isolation pattern on the contact layer (10), and etching with an inductively coupled plasma (BCl) by using a photoresist as a mask₃/Cl₂A gas source for etching the epitaxial material to form mesa isolation with a depth of 500nm-700 nm;

17) using electron beam lithography at n⁺Forming a circular pattern with the diameter of 1-4 mu m on the GaN emitter ohmic contact layer (10), evaporating a Ti/Au/Ni metal layer by using a photoresist as a mask and adopting an electron beam evaporation method to form an emitter electrode (11), and then adopting an inductively coupled plasma etching method by using a BCl (binary coded decimal fraction) by using the metal as the mask and adopting a BCl (binary coded decimal) method₃/Cl₂Gas source, etching depth to n⁺A GaN collector ohmic contact layer (4) forming a cylindrical mesa from the first GaN isolation layer (5) to the emitter electrode (11);

18) using conventional optical lithography, at n⁺Forming a ring pattern with the inner circumference being 3 mu m away from the cylindrical table top on the GaN collector ohmic contact layer (4), and evaporating the Ti/Au metal layer by adopting an electron beam evaporation method by taking photoresist as a mask to form a collector electrode (13);

19) using plasma enhanced chemical vapor deposition or atomic layer deposition process at n⁺A passivation layer (12) with the thickness of 50nm-200nm is deposited from the GaN collector ohmic contact layer (4) to the surface of the emitter electrode (11);

20) forming a collector electrode through hole pattern on the passivation layer (12) by using conventional optical lithography, and then using the photoresist as a mask, using a reactive ion etching method using SF₆A gas source forming a collector electrode through hole;

21) forming a circular pattern with a diameter of 500nm-3 μm on the passivation layer (12) by electron beam lithography, and then using the photoresist as a mask, using a reactive ion etching method using SF₆A gas source forming an emitter electrode through hole;

22) and forming an emitter and a collector Pad pattern on the surface of the device by adopting traditional optical lithography, evaporating the Ti/Au metal layer by adopting an electron beam evaporation method by taking the photoresist as a mask to form the emitter and the collector Pad, and finishing the preparation of the device.

5. The method of manufacturing of claim 4, wherein:

the metal organic chemical vapor deposition in the step 2) has the following process conditions: the temperature is 1150-1200 ℃, the pressure is 40Torr, the flow of ammonia gas is 2000sccm, the flow of aluminum source is 20sccm, the flow of gallium source is 90-120 sccm, and the flow of hydrogen is 3000 sccm;

the metal organic chemical vapor deposition process conditions in the step 10) are that the temperature is 1100-1200 ℃, the pressure is 40Torr, the flow of ammonia gas is 2000sccm, the flow of gallium source is 90-150 sccm, and the flow of hydrogen is 3000 sccm.

6. The method of claim 4, wherein: the microwave plasma chemical vapor deposition in the step 12) has the following process conditions: the temperature is 900-1000 ℃, the methane flow is 40-60 mL/min, the pressure is 160-190 Torr, the microwave power is 3.5-4.5 kW, the nitrogen flow is 70-90 muL/min, and the hydrogen flow is 550-650 mL/min.

7. The method of claim 4, wherein:

the molecular beam epitaxy method in the 3) and the 9) has the same process conditions, namely the temperature is 650-720 ℃, the equilibrium vapor pressure of the gallium beam is 7.5 multiplied by 10^-7Torr-8.5×10^-7Torr, equilibrium vapor pressure of silicon beam current is 3.0X 10^-8Torr-3.5×10^-8Torr, nitrogen flow rate is 2.3sccm, and nitrogen plasma radio frequency source power is 375W;

the molecular beam epitaxy method in the 4), 6) and 8) has the same technological conditions, namely the temperature is 650-720 ℃, the nitrogen flow is 2.3sccm, and the balance vapor pressure of the gallium beam is 7.5 multiplied by 10^-7Torr-8.5×10^-7Torr, the power of nitrogen plasma radio frequency source is 375W;

the molecular beam epitaxy method in the 5) and the 7) has the same technological conditions, namely the temperature is 650-720 ℃, the nitrogen flow is 2.3sccm, and the equilibrium vapor pressure of the aluminum beam is 2.3 multiplied by 10^-7Torr-2.8×10^-7Torr, equilibrium vapor pressure of gallium beam current is 7.5X 10^-7Torr, equilibrium vapor pressure of indium beam current is 1.6X 10^-7Torr, nitrogen plasma RF source power was 375W.

8. The method of claim 4, wherein:

the conventional optical lithography method in 16) has the following process conditions: using AZ5214 photoresist, firstly rotating at 500rad/min and accelerating at 1000rad^2/Spin coating for 3s at min, and rotating at 4000rad/min and 2000rad at acceleration²Spin coating for 30s at min, drying the glue for 90s, and controlling the temperature to be 95 ℃; the developer adopts RZX-3038, and the developing time is 45 s.

The electron beam lithography method adopted in 17) has the following process conditions: adopting PMMA A4 photoresist, wherein the photoresist drying time is 90s, the temperature is 180 ℃, the electron dose ratio is 750, the diameter of a photoetching circular pattern is 1-4 mu m, and the developer is 3: 1 tetramethylcyclopentanone and isopropanol for 120s, fixer isopropanol for 30 s.

9. The method of claim 4, wherein: the plasma enhanced chemical vapor deposition method adopted in the 19) has the following process conditions: at a pressure of 2200mTorr and a temperature of 350 ℃ and SiH₄Flow rate of 13.5sccm, NH₃The flow rate is 10sccm, N₂The flow rate is 1000sccm and the time is 30-120 s.

10. The method of claim 4, wherein: the inductively coupled plasma etching method in 16) has the following process conditions: cl₂The gas flow rate was 10sccm, BCl₃The gas flow is 25sccm, and the etching time is 300-420 s.

Technical Field

The invention belongs to the technical field of semiconductor devices, and particularly relates to a nitrogen polar surface gallium nitride resonant tunneling diode which can be used for a high-frequency terahertz radiation source and a high-speed digital circuit.

Background

The resonant tunneling diode is a quantum effect device with a vertical structure, has the characteristics of differential negative resistance, low junction capacitance, short carrier transport time and the like, and is an ideal device for preparing a high-frequency terahertz radiation source and a multi-value logic digital circuit. The high-frequency oscillator prepared based on the resonant tunneling diode is one of approaches for realizing terahertz radiation, and has potential application in safety detection, medical diagnosis and high-speed communication. Because the gallium nitride material has the advantages of wide forbidden band, high breakdown field strength, high saturated electron speed, high thermal conductivity and the like, the gallium nitride-based resonant tunneling diode can realize high-frequency and high-power output at room temperature. Meanwhile, the GaN-based resonant tunneling diode has a simple structure and is an effective way for exploring a related physical transport mechanism of a nitride device with a vertical structure. The conventional nitrogen polar plane gallium nitride resonant tunneling diode structure is shown in fig. 1, and comprises a substrate, a GaN epitaxial layer, and n from bottom to top⁺GaN collector ohmic contactContact layer, first GaN isolating layer, first barrier layer, GaN quantum well layer, second barrier layer, second GaN isolating layer and n⁺Ohmic contact layer of GaN emitter and emitter electrode at n⁺And the GaN collector ohmic contact layer is provided with an annular collector electrode. The device has the following 5 disadvantages:

1. the epitaxial polarity control difficulty of the nitrogen polar surface gallium nitride material is high, polarity inversion is easy to occur, and a mixed crystal phase of the gallium polar surface and the nitrogen polar surface appears.

2. The substrate thermal conductivity is low, the heat of the active region of the nitrogen polar surface gallium nitride resonant tunneling diode cannot be dissipated in time, the differential negative resistance effect of the device is reduced due to the heat accumulation effect, and the reliability and the stability of the device are deteriorated.

3. When the nitrogen polar surface gallium nitride resonant tunneling diode is peeled and transferred to the high-thermal conductivity diamond substrate, the device peeling and transferring process is complex, the roughness of a peeling interface is not smooth, the completeness of a peeled device is low, and the performance of the device after peeling and transferring is degraded.

4. The problems of large lattice mismatch, large crystal phase mismatch, large thermal mismatch and the like exist between the substrate diamond with high thermal conductivity and the gallium nitride material with the nitrogen polar surface which is directly grown, and the gallium nitride material with the nitrogen polar surface which is directly grown by heteroepitaxy on the substrate diamond is difficult to realize high crystallization quality.

5. The active area of the device is distributed unevenly in a staggered way, so that the leakage of the device is serious, the peak-to-valley current ratio and the differential negative resistance effect are deteriorated due to the rise of the valley current of the device, and the consistency of the performance of the device with the same size is poor.

At present, the gallium nitride-based resonant tunneling diode is mainly manufactured based on a gallium polar surface double-barrier single quantum well structure material, and because the material epitaxial growth technology and the device preparation process of a gallium polar surface device are mature, the high material quality and high performance device are easy to realize. Meanwhile, the device transport mechanism is deeply researched, and theoretical support is provided for the structural design of the high-performance device. However, the nitrogen polar plane gan resonant tunneling diode has many advantages. In the structural device, the emitter electrode is arranged on the top of the epitaxial material, so that the regulation and control on the tunneling carrier density can be enhanced. Meanwhile, the double-barrier structure and other functional materials are integrated on a single chip through the top emitter electrode. Seamless connection of the III-nitride semiconductor and other functional materials through the nitrogen polar gallium nitride resonant tunneling diode provides a way for exploring unknown device physics.

However, the nitride resonant tunneling diode with a nitrogen polar surface has major problems in the epitaxial growth of materials and the improvement of device performance. Firstly, polarity inversion is easy to occur in the epitaxial growth process of the nitrogen polar surface gallium nitride material, the polarity control difficulty is high, and a mixed phase of gallium polarity and nitrogen polarity is often generated. High-density dislocation defects exist in the heteroepitaxial nitrogen polar surface gallium nitride material, so that the roughness of the interface of an active region quantum well of the device is uneven, a leakage channel is formed, valley current is increased, and the differential negative resistance effect of the device is degraded. Secondly, the junction temperature of the device is rapidly increased due to the heat accumulation effect of the active region of the nitrogen polar surface gallium nitride resonant tunneling diode device, the self-heating effect is generated, and the stability and the repeatability of the differential negative resistance effect of the device are degraded. Therefore, in order to further improve the performance of the nitrogen-polarity gallium nitride resonant tunneling diode, a substrate with high thermal conductivity needs to be adopted, the heat transfer capacity near an active region is improved, the self-heating effect of the device is improved, and the reliability and the stability of the device are improved. Meanwhile, innovations need to be made on the epitaxial technology of the nitrogen polar surface gallium nitride material, so that the dislocation defect density in the heteroepitaxial nitrogen polar surface gallium nitride material is reduced, and the difficulty of the material polarity control process is reduced.

Disclosure of Invention

The invention aims to provide a nitrogen polar surface gallium nitride resonant tunneling diode and a manufacturing method thereof aiming at the defects of the prior art, so as to improve the epitaxial quality of materials, improve the self-heating effect of devices, improve the reliability and stability of the devices and simultaneously reduce the difficulty of the peeling and transferring processes of the devices.

The technical scheme of the invention is realized as follows:

1. a GaN resonant tunneling diode with nitrogen polar surface comprises, from bottom to top, a substrate and n⁺GaN collector ohmic contact layer, first GaN isolating layer, first barrier layer, GaN quantum well layer, second barrier layer, second GaN isolating layer, n⁺GaN emitter ohmic contactLayer, emitter electrode, first GaN isolation layer both sides are annular collector electrode, and first GaN isolation layer forms the cylinder platform to the etching of emitter electrode, and the outside parcel of this cylinder platform has passivation layer, its characterized in that:

the substrate is made of diamond material;

n is⁺A SiN transition layer and a GaN support layer are arranged between the GaN collector ohmic contact layer and the substrate for depositing the substrate and supporting the n of the resonant tunneling diode⁺And a GaN collector ohmic contact layer.

Further, the thickness of the SiN transition layer is 50nm-200 nm; the thickness of the GaN supporting layer is 4-10 mu m; the thickness of the substrate is 40-60 μm.

Further, n is⁺GaN collector ohmic contact layer and n⁺GaN emitter ohmic contact layer with doping concentration of 5 × 10¹⁹cm^-3-1×10²⁰cm^-3The thickness is 100nm-300 nm; the thicknesses of the first GaN isolating layer and the second GaN isolating layer are 4nm-8 nm; the first barrier layer and the second barrier layer adopt any one of AlN, AlGaN and InAlN, and the thickness of the first barrier layer and the second barrier layer is 1nm-3 nm; the thickness of the GaN quantum well layer is 1nm-3 nm; the passivation layer is made of SiN material and Al₂O₃Material, HfO₂Any one of the materials.

2. A method for manufacturing a nitrogen polar surface gallium nitride resonant tunneling diode is characterized by comprising the following steps:

1) on a self-supporting gallium nitride epitaxial wafer, graphene, BN and MoS with the thickness of 2nm-5nm are grown by utilizing a chemical vapor deposition process₂Any one of the transfer layers;

2) sequentially growing a GaN or AlN nucleating layer with the thickness of 50nm-200nm and a GaN buffer layer with the thickness of 1000nm-3000nm on the transfer layer by using a metal organic chemical vapor deposition process;

3) growing n on the buffer layer by molecular beam epitaxy⁺The thickness of the GaN emitter ohmic contact layer is 100nm-300nm, and the doping concentration is 5 multiplied by 10¹⁹cm^-3-1×10²⁰cm^-3；

4) By molecular beam epitaxy method at n⁺A second GaN isolating layer with the thickness of 4nm-8nm is grown on the GaN emitting electrode ohmic contact layer;

5) growing a second barrier layer with the thickness of 1nm-3nm on the second GaN isolating layer by adopting a molecular beam epitaxy method;

6) growing a GaN quantum well layer with the thickness of 1nm-3nm on the second barrier layer by adopting a molecular beam epitaxy method;

7) growing a first barrier layer with the thickness of 1nm-3nm on the GaN quantum well layer by adopting a molecular beam epitaxy method;

8) growing a first GaN isolating layer with the thickness of 4nm-8nm on the first barrier layer by adopting a molecular beam epitaxy method;

9) growing n on the first GaN isolating layer by molecular beam epitaxy method⁺The thickness of the GaN collector ohmic contact layer is 100nm-300nm, and the doping concentration is 5 multiplied by 10¹⁹cm^-3-1×10²⁰cm^-3；

10) Using a metal organic chemical vapor deposition process at n⁺A GaN supporting layer with the thickness of 4-10 mu m is deposited on the GaN collector ohmic contact layer;

11) depositing a SiN transition layer with the thickness of 50nm-200nm on the GaN supporting layer by using a low-pressure chemical vapor deposition technology;

12) depositing a diamond substrate with the thickness of 40-60 mu m on the SiN transition layer by using a microwave plasma chemical vapor deposition process;

13) stripping the self-supporting gallium nitride epitaxial wafer and the transfer layer;

14) removing the nucleating layer and the buffer layer by using an etching technology;

15) n is to be⁺The GaN emitter ohmic contact layer and the upper part of the GaN emitter ohmic contact layer are integrally turned over up and down;

16) using conventional optical lithography, at n⁺Forming a mesa isolation pattern on the GaN emitter ohmic contact layer, and etching with an inductively coupled plasma (BCl) by using photoresist as a mask₃/Cl₂A gas source for etching the epitaxial material to form mesa isolation with a depth of 500nm-700 nm;

17) using electron beam lithography at n⁺Forming a circular pattern with the diameter of 1-4 μm on the ohmic contact layer of the GaN emitter, evaporating a Ti/Au/Ni metal layer by using a photoresist as a mask and adopting an electron beam evaporation method to form an emitter electrode, then using the metal as the mask and adopting an inductively coupled plasma etching method and using BCl₃/Cl₂Gas source, etching depth to n⁺A GaN collector ohmic contact layer forming a cylindrical mesa from the first GaN isolation layer to the emitter electrode;

18) using conventional optical lithography, at n⁺Forming a circular ring pattern with the inner circumference being 3 mu m away from the cylindrical table top on the GaN collector ohmic contact layer, and evaporating the Ti/Au metal layer by adopting an electron beam evaporation method by taking the photoresist as a mask to form a collector electrode;

19) using plasma enhanced chemical vapor deposition or atomic layer deposition process at n⁺Depositing a passivation layer with the thickness of 50nm-200nm from the GaN collector ohmic contact layer to the surface of the emitter electrode;

20) forming a collector electrode through hole pattern on the passivation layer by using conventional optical lithography, and performing reactive ion etching (SF) by using the photoresist as a mask₆A gas source forming a collector electrode through hole;

21) forming a circular pattern with a diameter of 500nm-3 μm on the passivation layer by electron beam lithography, and etching with the photoresist as a mask by reactive ion etching (SF)₆A gas source forming an emitter electrode through hole;

22) and forming an emitter and a collector Pad pattern on the surface of the device by adopting traditional optical lithography, evaporating the Ti/Au metal layer by adopting an electron beam evaporation method by taking the photoresist as a mask to form the emitter and the collector Pad, and finishing the preparation of the device.

Compared with the prior art, the invention has the following advantages:

1. the device of the invention can use diamond with high thermal conductivity as the substrate due to the addition of the SiN transition layer, thereby improving the heat dissipation capability of the resonant tunneling diode, improving the heat accumulation effect and improving the stability and reliability of the differential negative resistance effect of the device.

2. The device can directly grow the diamond substrate on the gallium nitride material due to the additional GaN supporting layer, so that the preparation of the nitrogen polar surface gallium nitride resonant tunneling diode on the high-thermal-conductivity diamond substrate is realized, and the problems of lattice mismatch, crystal phase mismatch and thermal mismatch existing in the heteroepitaxy nitrogen polar surface gallium nitride material directly on the diamond substrate are avoided.

3. The device of the invention adopts the mode of stripping and turning the grown gallium polar surface gallium nitride material, thereby reducing the process control difficulty of directly epitaxially growing the nitrogen polar surface gallium nitride material and realizing the preparation of the nitrogen polar surface gallium nitride resonant tunneling diode with high quality and low dislocation density.

4. The device is prepared by adopting graphene, BN or MoS₂The two-dimensional material is used as a transfer layer to realize device stripping, so that the epitaxial gallium nitride material stripping process can be simplified, and the rough stripping interface caused by directly etching and stripping the epitaxial layer is avoided, so that a smooth and flat stripping interface can be obtained, and large-area stripping is realized.

5. The device of the invention has simple preparation and stripping process and high process repeatability and consistency, and can avoid the attenuation of the differential negative resistance effect of the device after stripping.

Drawings

FIG. 1 is a block diagram of a conventional GaN resonant tunneling diode with a nitrogen-polarity surface;

FIG. 2 is a structural diagram of a GaN resonant tunneling diode with a nitrogen polar surface according to the present invention;

FIG. 3 is a schematic flow chart of the fabrication of a GaN resonant tunneling diode with a nitrogen polar surface according to the present invention.

Detailed Description

Referring to fig. 2, the nitrogen polar surface gallium nitride resonant tunneling diode of the invention comprises a substrate 1, a SiN transition layer 2, a GaN supporting layer 3, n from bottom to top⁺A GaN collector ohmic contact layer 4, a first GaN isolating layer 5, a first barrier layer 6, a GaN quantum well layer 7, a second barrier layer 8, a second GaN isolating layer 9, n⁺A GaN emitter ohmic contact layer 10, an emitter electrode 11, a ring-shaped collector electrode 13 arranged at two sides of the first GaN isolating layer 5, a first GaN isolating layerThe GaN isolating layer 5 to the emitter electrode 11 are etched to form a cylindrical table, and the outside of the cylindrical table is wrapped with a passivation layer 12.

The substrate 1 is made of diamond, and the thickness of the substrate is 40-60 mu m;

the thickness of the SiN transition layer 2 is 50nm-200 nm;

the thickness of the GaN supporting layer 3 is 4-10 mu m;

n is⁺GaN collector ohmic contact layer 4 and n⁺A GaN emitter ohmic contact layer 10 with a doping concentration of 5 × 10¹⁹cm^-3-1×10²⁰cm^-3The thickness is 100nm-300 nm;

the thicknesses of the first GaN isolating layer 5 and the second GaN isolating layer 9 are 4nm-8 nm;

the first barrier layer 6 and the second barrier layer 8 adopt any one of AlN, InAlN and AlGaN, and the thickness of the first barrier layer and the second barrier layer is 1nm-3 nm;

the thickness of the GaN quantum well layer 7 is 1nm-3 nm;

the passivation layer 12 is made of SiN material and Al₂O₃Material, HfO₂Any one of the materials.

Referring to fig. 3, the nitrogen polar plane gan resonant tunneling diode and the method for fabricating the same according to the present invention provide the following three embodiments.

In the first embodiment, a gan resonant tunneling diode with graphene as a transfer layer, 1.5nm AlN as a barrier layer, and 200nm SiN as a passivation layer was fabricated.

Step one, a self-supporting gan epitaxial wafer is selected as an auxiliary epitaxial substrate, as shown in fig. 3 (a).

Step two, depositing a graphene transfer layer, as shown in fig. 3 (b).

And depositing a graphene transfer layer with the thickness of 5nm on the self-supporting gallium nitride epitaxial wafer by using a chemical vapor deposition technology.

The process conditions for depositing the graphene transfer layer are as follows: the temperature is 800 ℃, the methane flow is 25mL/min, the argon flow is 350mL/min, and the hydrogen flow is 15 mL/min.

Step three, an AlN nucleation layer is deposited, as in fig. 3 (c).

And depositing an AlN nucleating layer with the thickness of 200nm on the graphene transfer layer by using a metal organic chemical vapor deposition technology.

The process conditions for depositing the AlN nucleating layer are as follows: the temperature was 1150 deg.C, the pressure was 40Torr, the flow of ammonia gas was 2000sccm, the flow of aluminum source was 20sccm, and the flow of hydrogen gas was 3000 sccm.

Step four, depositing a GaN buffer layer, as shown in FIG. 3 (d).

And depositing a GaN buffer layer with the thickness of 1000nm on the AlN nucleating layer by using a metal organic chemical vapor deposition technology.

The technological conditions for depositing the GaN buffer layer are as follows: the temperature was 1150 deg.C, the pressure was 40Torr, the flow of ammonia gas was 2000sccm, the flow of gallium source was 100sccm, and the flow of hydrogen was 3000 sccm.

Step five, depositing n⁺And (e) a GaN emitter ohmic contact layer as shown in FIG. 3 (e).

Growing a GaN buffer layer with a thickness of 100nm and a doping concentration of 1 × 10 by molecular beam epitaxy²⁰cm^-3N of (A) to (B)⁺And a GaN emitter ohmic contact layer.

Deposition of n⁺The process conditions of the GaN emitter ohmic contact layer are as follows: the temperature is 700 ℃, the equilibrium vapor pressure of the gallium beam is 8.0 multiplied by 10^-7Torr, equilibrium vapor pressure of silicon beam stream is 3.5X 10^-8The nitrogen flow rate was 2.3sccm and the nitrogen plasma RF source power was 375W.

Step six, a second GaN isolation layer is deposited, as shown in fig. 3 (f).

By molecular beam epitaxy method at n⁺And a second GaN isolating layer with the thickness of 8nm is deposited on the GaN emitting electrode ohmic contact layer.

The process conditions for depositing the second GaN isolating layer are as follows: the temperature is 700 ℃, the equilibrium vapor pressure of the gallium beam is 8.0 multiplied by 10^{- 7}The nitrogen flow rate was 2.3sccm and the nitrogen plasma RF source power was 375W.

Step seven, deposit the second AlN barrier layer, as in figure 3 (g).

And depositing a second AlN barrier layer with the thickness of 1.5nm on the second GaN isolating layer by adopting a molecular beam epitaxy method.

The process conditions for depositing the second AlN barrier layer are as follows: the temperature is 700 ℃, the nitrogen flow is 2.3sccm, and the equilibrium vapor pressure of the aluminum beam is 2.5 multiplied by 10^-7Torr, nitrogen plasma RF source power was 375W.

Step eight, depositing a GaN quantum well layer as shown in FIG. 3 (h).

And depositing a GaN quantum well layer with the thickness of 2.5nm on the second AlN barrier layer by adopting a molecular beam epitaxy method.

The technological conditions for depositing the GaN quantum well layer are as follows: the temperature is 700 ℃, the equilibrium vapor pressure of the gallium beam is 8.0 multiplied by 10^{- 7}The nitrogen flow rate was 2.3sccm and the nitrogen plasma RF source power was 375W.

Step nine, deposit the first AlN barrier layer, as in fig. 3 (i).

And depositing a first AlN barrier layer with the thickness of 1.5nm on the GaN quantum well layer by adopting a molecular beam epitaxy method.

The process conditions for depositing the first AlN barrier layer are as follows: the temperature is 700 ℃, the nitrogen flow is 2.3sccm, and the equilibrium vapor pressure of the aluminum beam is 2.5 multiplied by 10^-7Torr, nitrogen plasma RF source power was 375W.

Step ten, deposit the first GaN isolation layer, as shown in fig. 3 (j).

A first GaN isolation layer with a thickness of 8nm was deposited on the first AlN barrier layer by a molecular beam epitaxy method.

The process conditions for depositing the first GaN isolating layer are as follows: the temperature is 700 ℃, the equilibrium vapor pressure of the gallium beam is 8.0 multiplied by 10^{- 7}The nitrogen flow rate was 2.3sccm and the nitrogen plasma RF source power was 375W.

Step eleven, depositing n⁺And a GaN collector ohmic contact layer as shown in FIG. 3 (k).

Depositing a first GaN isolating layer with a thickness of 100nm and a doping concentration of 1 × 10 by molecular beam epitaxy²⁰cm^-3N of (A) to (B)⁺And a GaN collector ohmic contact layer.

Deposition of n⁺The technological conditions of the GaN collector ohmic contact layer are as follows: the temperature is 700 ℃, and gallium beam current equilibrium evaporation is carried outThe air pressure is 8.0 x 10^-7Torr, equilibrium vapor pressure of silicon beam stream is 3.5X 10^-8The nitrogen flow rate was 2.3sccm and the nitrogen plasma RF source power was 375W.

Step twelve, a GaN support layer is deposited, as shown in FIG. 3 (l).

Using metal organic chemical vapor deposition techniques at n⁺And a GaN supporting layer with the thickness of 4 mu m is deposited on the GaN collector ohmic contact layer.

The technological conditions adopted for depositing the GaN supporting layer are as follows: the temperature was 1150 deg.C, the pressure was 40Torr, the flow of ammonia gas was 2000sccm, the flow of gallium source was 90sccm, and the flow of hydrogen was 3000 sccm.

Thirteen, a 100nm thick SiN transition layer was deposited on the GaN support layer using low pressure chemical vapor deposition techniques, as shown in fig. 3 (m).

Fourteen, deposit the diamond substrate, as shown in fig. 3 (n).

A diamond substrate having a thickness of 40 μm was deposited on the SiN transition layer using a microwave plasma chemical vapour deposition technique.

The process conditions adopted for depositing the diamond substrate are as follows: the temperature was 900 ℃, the methane flow rate was 40mL/min, the pressure was 160Torr, the microwave power was 3.5kW, the nitrogen flow rate was 70. mu.L/min, and the hydrogen flow rate was 550 mL/min.

And a fifteenth step of stripping the self-supporting GaN epitaxial wafer and the transfer layer, as shown in FIG. 3 (o).

Sixthly, the nucleation layer and the buffer layer are removed by using an etching technology, as shown in fig. 3 (p).

Seventhly, mixing n⁺The GaN emitter ohmic contact layer and the upper portion thereof are entirely turned upside down as shown in FIG. 3 (q).

After turning over, the diamond substrate, the SiN transition layer, the GaN supporting layer and n are arranged from bottom to top⁺A GaN collector ohmic contact layer, a first GaN isolation layer, a first AlN barrier layer, a GaN quantum well layer, a second AlN barrier layer, a second GaN isolation layer, and an n⁺And a GaN emitter ohmic contact layer.

Eighteen, in n⁺Photoresist homogenizing, photoetching, developing and etching are carried out on the ohmic contact layer of the GaN emitter to form a grid shape with the depth of 500nmMesa isolation, as in fig. 3 (r).

18a) Forming a mesa isolation pattern by photolithography:

18a1) spin coating AZ5214 photoresist at 500rad/min and 1000rad acceleration^2/Spin coating for 3s at min; then the rotation speed is 4000rad/min, the acceleration is 2000rad²Spin coating for 30s at min, and baking for 90s at 95 deg.C;

18a2) using conventional optical lithography, for n⁺Exposing AZ5214 photoresist on the GaN emitter ohmic contact layer;

18a3) developing the photoresist after exposure treatment by adopting an RZX-3038 developing solution for 45s to form a grid-shaped mesa isolation graph;

18b) etching to form mesa isolation:

and etching to form a grid-shaped mesa isolation with the depth of 500nm by using the photoresist as a mask by adopting an inductively coupled plasma etching method.

The process conditions adopted by the inductively coupled plasma etching are as follows: cl₂The gas flow rate was 10sccm, BCl₃The flow rate was 25sccm and the etching time was 300 s.

Nineteen steps, in n⁺Etching the ohmic contact layer of the GaN emitting electrode to n⁺A GaN collector ohmic contact layer, a cylindrical mesa having a diameter of 2 μm was formed, and metal was deposited to form an emitter electrode, as shown in fig. 3(s).

19a) Photoetching to form a circular mesa pattern:

19a1) at n⁺The ohmic contact layer of the GaN emitter is spin-coated with PMMA A4 photoresist, and then the rotation speed is 500rad/min, the acceleration is 1000rad^2/Spin coating for 3s at min, and rotating at 4000rad/min and 2000rad at acceleration²Spin coating for 30s at min, and baking at 180 deg.C for 90 s;

19a2) adopting an electron beam lithography method, setting an electron dose ratio to be 750, and carrying out exposure treatment on the PMMA A4 photoresist;

19a3) firstly, the proportion of 3: developing the exposed photoresist for 120s by using tetramethylcyclopentanone and isopropanol solution of 1, and fixing for 30s by using isopropanol to form a circular mesa pattern with the diameter of 2 microns;

19b) by electron beam evaporation on a circular tableEvaporating Ti/Au/Ni metal with the thickness of 20/80/50nm at the speed of the first step, and then soaking the Ti/Au/Ni metal in an acetone solution;

19c) etching n with metal as mask by inductively coupled plasma etching method⁺GaN emitter ohmic contact layer to n⁺And the GaN collector ohmic contact layer forms a cylindrical mesa with the diameter of 2 mu m.

The process conditions adopted by the inductively coupled plasma etching are as follows: cl₂The gas flow rate was 10sccm, BCl₃The flow rate was 25sccm and the etching time was 150 s.

Twenty, at n⁺A ring-shaped collector electrode having an inner circumference of 3 μm from the cylindrical mesa was formed on the GaN collector ohmic contact layer as shown in fig. 3 (t).

20a) And forming a ring-shaped collector electrode pattern by photoetching:

20a1) at n⁺An AZ5214 photoresist is spin-coated on the ohmic contact layer of the GaN collector, and the rotation speed is 500rad/min, the acceleration is 1000rad^2/Spin coating for 3s at min, and rotating at 4000rad/min at an acceleration of 2000rad²Spin coating for 30s at min, and baking for 90s at 95 deg.C;

20a2) using conventional optical lithography, for n⁺Exposing AZ5214 photoresist on the GaN collector ohmic contact layer;

20a3) developing the photoresist after exposure treatment for 45s by adopting RZX-3038 developing solution to form an annular collector electrode pattern with the inner circumference being 3 mu m away from the cylindrical table top;

20b) using electron beam evaporation at n⁺On the ohmic contact layer of GaN collectorThe Ti/Au metal was evaporated at a thickness of 20/80nm and then soaked in an acetone solution to form a collector electrode having an inner circumference of 3 μm from the surface of the cylindrical mesa.

Step twenty one, a passivation layer is deposited, as in fig. 3 (u).

And depositing a SiN passivation layer with the thickness of 200nm on the surface of the whole device by adopting a plasma enhanced chemical vapor deposition method.

The plasma enhanced chemical vapor deposition method adopts the following process conditions: time 60s, pressure 2200mTorr, temperature 350 deg.C, SiH₄Flow rate of 13.5sccm, NH₃The flow rate is 10sccm, N₂The flow rate was 1000 sccm.

And twenty-two steps, photoetching and etching are carried out on the SiN passivation layer to form a collector through hole, and the step (v) is shown in FIG. 3.

22a) And photoetching to form a collector through hole pattern:

22a1) an AZ5214 photoresist is spin-coated on the SiN passivation layer at a rotation speed of 500rad/min and an acceleration of 1000rad^2/Spin coating for 3s at min, and rotating at 4000rad/min at an acceleration of 2000rad²Rotating for 30s at min, and baking for 90s at 95 ℃;

22a2) performing exposure treatment on the AZ5214 photoresist on the SiN passivation layer by adopting traditional optical lithography;

22a3) and developing the photoresist subjected to exposure treatment for 45s by adopting an RZX-3038 developing solution to form a circular ring pattern with the inner diameter slightly smaller than that of the collector electrode.

22b) And etching the SiN passivation layer to the metal surface of the collector electrode by using the photoresist as a mask by adopting a reactive ion etching method to form a collector through hole.

The reactive ion etching method adopts the following process conditions: pressure 1500mTorr, power 200W, SF₆Flow rate of 8sccm, CHF₃At 10sccm, and a He flow rate of 150 sccm.

Twenty-three steps, an emitter electrode via hole having a diameter of 1 μm is prepared on the passivation layer of SiN, as shown in fig. 3 (w).

23a) And (3) forming an emitter electrode through hole pattern by photoetching:

23a1) PMMA A4 photoresist is spin-coated on the passivation layer of SiN, i.e. the rotation speed is 500rad/min, the acceleration is 1000rad^2/Spin coating for 3s at min, and rotating at 4000rad/min at an acceleration of 2000rad²Spin coating for 30s at min, and baking for 90s at 180 deg.C;

23a2) setting the electron dose ratio to be 750, and carrying out exposure treatment on the PMMA A4 photoresist by adopting an electron beam lithography method;

23a3) for the photoresist after exposure treatment, the proportion of 3: developing the solution of tetramethyl-cyclopentanone and isopropanol of the step 1 for 120s, and fixing the solution for 30s by using isopropanol to form a through hole pattern of an emitter electrode;

23b) and etching the SiN passivation layer to the metal surface of the emitter electrode by using the photoresist as a mask through a reactive ion etching method to form the emitter electrode through hole with the diameter of 1 micrometer.

The reactive ion etching method adopts the following process conditions: pressure 1500mTorr, power 200W, SF₆Flow rate of 8sccm, CHF₃At 10sccm, and a He flow rate of 150 sccm.

And twenty-four steps, leading out the emitter electrode Pad and the collector electrode Pad on the emitter electrode through hole and the collector electrode through hole, and finishing the manufacture of the device, as shown in fig. 3 (x).

24a) And photoetching to form an emitter electrode metal and a collector electrode metal Pad pattern:

24a1) the through hole of the emitter and the collector is coated with AZ5214 photoresist in a spinning way, namely, the rotating speed is 500rad/min, the acceleration is 1000rad^2/Spin coating for 3s at min, and rotating at 4000rad/min at an acceleration of 2000rad²Spin coating for 30s at min, and baking for 90s at 95 deg.C;

24a2) carrying out exposure treatment on the AZ5214 photoresist by adopting a traditional optical photoetching method;

24a3) developing the exposed photoresist for 45s by adopting an RZX-3038 developing solution to form an emitter electrode and collector electrode metal Pad graph;

24b) using an electron beam evaporation method, according toEvaporating Ti/Au metal with the thickness of 20/80nm at the speed, and soaking the Ti/Au metal by using acetone to form an emitter electrode Pad and a collector electrode Pad which are interconnected with the emitter electrode and the collector electrode, thereby completing the manufacture of the device.

Example two, manufacture with MoS₂As a transfer layer, a barrierThe layer adopts InAlN with the thickness of 1nm, and the passivation layer adopts Al with the thickness of 50nm₂O₃The nitrogen polar plane gallium nitride resonant tunneling diode.

Step 1, selecting a self-supporting gan epitaxial wafer as an auxiliary epitaxial substrate, as shown in fig. 3 (a).

Step 2, MoS is deposited by using chemical vapor deposition technology₂Transfer layer, as in fig. 3 (b).

Using chemical vapor deposition technique at 800 deg.C under nitrogen flow of 200sccm and MoO₃MoS with the thickness of 3nm is deposited on the gallium nitride epitaxial wafer under the process conditions that the dosage is 0.2g and the dosage of sulfur powder is 2g₂And (3) transferring the layer.

Step 3, depositing a GaN nucleation layer by using a metal organic chemical vapor deposition (mocvd) technique, as shown in fig. 3 (c).

Using metal organic chemical vapor deposition technology, under the process conditions of 1200 ℃ of temperature, 40Torr of pressure, 2000sccm of ammonia gas flow, 120sccm of gallium source flow and 3000sccm of hydrogen gas flow, in MoS₂A GaN nucleation layer with a thickness of 50nm was deposited on the transfer layer.

Step 4, depositing a GaN buffer layer by using a metal organic chemical vapor deposition (mocvd) technique, as shown in fig. 3 (d).

And depositing a GaN buffer layer with the thickness of 2000nm on the GaN nucleating layer by using a metal organic chemical vapor deposition technology under the process conditions that the temperature is 1200 ℃, the pressure is 40Torr, the flow of ammonia gas is 2000sccm, the flow of a gallium source is 120sccm and the flow of hydrogen is 3000 sccm.

Step 5, using molecular beam epitaxy method to deposit n⁺And (e) a GaN emitter ohmic contact layer as shown in FIG. 3 (e).

Using molecular beam epitaxy method, at 650 deg.C, the equilibrium vapor pressure of gallium beam is 8.5 × 10^-7Torr, equilibrium vapor pressure of silicon beam stream is 3.2X 10^-8Torr, nitrogen flow rate of 2.3sccm, and nitrogen plasma RF source power of 375W, on the GaN buffer layer, a thickness of 200nm and a doping concentration of 8 × 10¹⁹cm^-3N of (A) to (B)⁺And a GaN emitter ohmic contact layer.

Step 6, a second GaN isolation layer is deposited using molecular beam epitaxy, as shown in fig. 3 (f).

Using molecular beam epitaxy method, adopting the conditions of 650 deg.C and gallium beam equilibrium vapor pressure of 8.5 × 10^-7Torr, nitrogen flow rate of 2.3sccm, nitrogen plasma RF source power of 375W, at n⁺And a second GaN isolating layer with the thickness of 6nm is deposited on the GaN emitting electrode ohmic contact layer.

Step 7, depositing the second In by using molecular beam epitaxy method_0.17Al_0.83N barrier layer, FIG. 3 (g).

Using molecular beam epitaxy method, setting temperature at 650 deg.C, nitrogen flow at 2.3sccm, and indium beam equilibrium vapor pressure at 1.6 × 10^-7Torr, the equilibrium vapor pressure of aluminum beam is 2.3X 10^-7Torr, nitrogen plasma RF source power is 375W, and a second In with a thickness of 1nm and an In composition of 17% is deposited on the second GaN isolation layer_0.17Al_0.83An N barrier layer.

Step 8, depositing a GaN quantum well layer by using a molecular beam epitaxy method, as shown in FIG. 3 (h).

Using molecular beam epitaxy method, setting temperature at 650 deg.C and gallium beam equilibrium vapor pressure at 8.5 × 10^-7And (5) depositing a GaN quantum well layer with the thickness of 3nm on the second InAlN barrier layer under the process conditions that the nitrogen flow is 2.3sccm and the nitrogen plasma radio frequency source power is 375W.

Step 9, depositing the first In by using molecular beam epitaxy method_0.17Al_0.83N barrier layer, FIG. 3 (g).

Using molecular beam epitaxy method, setting temperature at 650 deg.C, nitrogen flow at 2.3sccm, and indium beam equilibrium vapor pressure at 1.6 × 10^-7Torr, the equilibrium vapor pressure of aluminum beam is 2.3X 10^-7Torr, the process condition of nitrogen plasma radio frequency source power of 375W, and first In with the thickness of 1nm and the In component of 17 percent is deposited on the GaN quantum well layer_0.17Al_0.83An N barrier layer.

Step 10, a first GaN isolation layer is deposited using molecular beam epitaxy, as shown in fig. 3 (j).

Using molecular beam epitaxy method with a temperature of 6At 50 deg.C, the equilibrium vapor pressure of gallium beam is 8.5X 10^-7And (3) under the process conditions of the Torr, the nitrogen flow of 2.3sccm and the nitrogen plasma radio frequency source power of 375W, depositing a first GaN isolating layer with the thickness of 6nm on the first InAlN barrier layer.

Step 11, depositing n by using molecular beam epitaxy method⁺And a GaN collector ohmic contact layer as shown in FIG. 3 (k).

Using molecular beam epitaxy method, at 650 deg.C, the equilibrium vapor pressure of gallium beam is 8.5 × 10^-7Torr, equilibrium vapor pressure of silicon beam stream is 3.2X 10^-8Torr, nitrogen flow rate of 2.3sccm, and nitrogen plasma RF source power of 375W, depositing a thickness of 200nm and a doping concentration of 8 × 10 on the first GaN isolation layer¹⁹cm^-3N of (A) to (B)⁺And a GaN collector ohmic contact layer.

Step 12, a GaN support layer is deposited using a metal organic chemical vapor deposition technique, as shown in fig. 3 (l).

Using metal organic chemical vapor deposition technology, under the process conditions of 1200 ℃ of temperature, 40Torr of pressure, 2000sccm of ammonia gas flow, 150sccm of gallium source flow and 3000sccm of hydrogen gas flow⁺And a GaN supporting layer with the thickness of 10 mu m is deposited on the GaN collector ohmic contact layer.

Step 13, using low pressure chemical vapor deposition technique, a SiN transition layer with a thickness of 50nm is deposited on the GaN support layer, as shown in fig. 3 (m).

Step 14, a diamond substrate is deposited using microwave plasma chemical vapor deposition techniques, as shown in fig. 3 (n).

A diamond substrate with a thickness of 50 μm was deposited on the SiN transition layer by microwave plasma chemical vapor deposition at a temperature of 950 deg.C, a methane flow of 50mL/min, a pressure of 180Torr, a microwave power of 4.0kW, a nitrogen flow of 80 μ L/min, and a hydrogen flow of 600 mL/min.

Step 15, lift off the self-supporting GaN epitaxial wafer and the transfer layer, as shown in FIG. 3 (o).

At step 16, the nucleation and buffer layers are removed using an etching technique, as shown in fig. 3 (p).

Step 17, mixingn⁺The GaN emitter ohmic contact layer and the upper portion thereof are entirely turned upside down as shown in FIG. 3 (q).

After turning over, the diamond substrate, the SiN transition layer, the GaN supporting layer and n are arranged from bottom to top⁺GaN collector ohmic contact layer, first GaN isolating layer, first InAlN barrier layer, GaN quantum well layer, second InAlN barrier layer, second GaN isolating layer, n⁺And a GaN emitter ohmic contact layer.

Step 18, at n⁺And (3) photoresist homogenizing, photoetching, developing and etching are carried out on the GaN emitter ohmic contact layer to form a grid-shaped mesa isolation with the depth of 600nm, as shown in figure 3 (r).

18.1) forming mesa isolation patterns using photolithography:

the specific implementation of this step is the same as step 18a) of the first embodiment.

18.2) etching to form mesa isolation:

adopting an inductively coupled plasma etching method, using photoresist as a mask and Cl₂The gas flow rate was 10sccm, BCl₃Etching n under the process condition that the gas flow is 25sccm⁺And the GaN emitter ohmic contact layer 360s forms a grid-shaped mesa isolation with the depth of 600 nm.

Step 19, at n⁺Etching the ohmic contact layer of the GaN emitting electrode to n⁺A GaN collector ohmic contact layer, a cylindrical mesa having a diameter of 1 μm was formed, and metal was deposited to form an emitter electrode, as shown in fig. 3(s).

19.1) photoetching to form a circular mesa pattern:

19.1a) at n⁺Spin-coating PMMA A4 photoresist on the GaN emitter ohmic contact layer twice: the first time at a rotation speed of 500rad/min and an acceleration of 1000rad^2/Spin coating for 3s at min; the second rotation speed is 4000rad/min and the acceleration is 2000rad²Spin coating for 30s at min, and baking at 180 deg.C for 90 s;

19.1b) adopting an electron beam lithography method, setting an electron dose ratio to be 750, and carrying out exposure treatment on the PMMA A4 photoresist;

19.1c) for the photoresist after exposure treatment, firstly adopting a ratio of 3: 1, developing with isopropanol solution for 120s, and fixing with isopropanol for 30s to form a circular mesa pattern with a diameter of 1 μm.

19.2) using electron beam evaporation method, on the circular table surface pattern according toThe Ti/Au/Ni metal was evaporated to a thickness of 20/80/50nm and then soaked in an acetone solution.

19.3) etching to form a cylindrical table-board, namely etching the circular table-board pattern by using metal as a mask and adopting an inductively coupled plasma etching method and setting Cl₂The gas flow rate was 10sccm, BCl₃Etching to n under the process conditions of the gas flow of 25sccm and the etching time of 150s⁺And the GaN collector ohmic contact layer forms a cylindrical mesa with the diameter of 1 mu m.

Step 20, at n⁺A ring-shaped collector electrode having an inner circumference of 3 μm from the cylindrical mesa was formed on the GaN collector ohmic contact layer as shown in fig. 3 (t).

The specific implementation of this step is the same as step twenty of the first embodiment.

Step 21, depositing 50nm Al₂O₃Dielectric passivation layer, as shown in fig. 3 (u).

Using an atomic layer deposition process with a set time of 40s, a pressure of 2000mTorr, a temperature of 300 deg.C, Al (CH)₃)₃The flow rate was 850sccm, H₂O flow rate of 350sccm, N₂The flow rate is 1000sccm, and Al with the thickness of 50nm is deposited on the whole surface of the device₂O₃A dielectric passivation layer.

Step 22, in Al₂O₃And photoetching and etching are carried out on the dielectric passivation layer to form a collector electrode through hole, as shown in figure 3 (v).

22.1) photoetching to form a collector electrode through hole pattern:

the specific implementation of this step is the same as step 22a) of the first embodiment.

22.2) etching to form a collector electrode through hole: the photoresist is used as a mask, the pressure is set to be 1500mTorr, the power is set to be 200W, and the SF is set to be₆Flow rate of 8sccm, CHF₃10sccm, the He flow rate is 150sccm, a reactive ion etching method is adopted,etching of Al₂O₃And a medium passivation layer is coated on the metal surface of the collector electrode to form a collector electrode through hole.

Step 23, in Al₂O₃Emitter electrode vias with a diameter of 500nm were prepared on the dielectric passivation layer as shown in fig. 3 (w).

23.1) photoetching to form an emitter electrode through hole pattern:

the specific implementation of this step is the same as step 23a) of the first embodiment.

23.2) etching to form an emitter electrode through hole: using photoresist as mask, adopting reactive ion etching method, under the conditions of pressure of 1500mTorr, power of 200W and SF₆Flow rate of 8sccm, CHF₃Etching Al with a He flow of 150sccm of 10sccm₂O₃And (4) a medium passivation layer is formed on the metal surface of the emitter electrode to form an emitter electrode through hole with the diameter of 500 nm.

And 24, leading out the emitter electrode Pad and the collector electrode Pad on the emitter electrode through hole and the collector electrode through hole to finish the manufacture of the device, as shown in fig. 3 (x).

The specific implementation of this step is the same as twenty-four steps of the first embodiment.

In the third embodiment, BN was used as the transfer layer, AlGaN with a thickness of 3nm was used as the barrier layer, and HfO with a thickness of 100nm was used as the passivation layer₂The nitrogen polar plane gallium nitride resonant tunneling diode.

Step a, selecting a self-supporting gan epitaxial wafer as an auxiliary epitaxial substrate, as shown in fig. 3 (a).

And step B, depositing a BN transfer layer with the thickness of 2nm on the gallium nitride epitaxial wafer by using a metal organic chemical vapor deposition technology and setting the process conditions of 1050 ℃ of temperature, 600Torr of pressure, 25 mu mol/min of triethylboron flow and 1500sccm of ammonia gas flow, as shown in a figure 3 (B).

And step C, depositing an AlN nucleating layer with the thickness of 100nm on the BN transfer layer by using a metal organic chemical vapor deposition technology under the process conditions that the temperature is 1200 ℃, the pressure is 40Torr, the ammonia gas flow is 2000sccm, the aluminum source flow is 20sccm and the hydrogen gas flow is 3000sccm, as shown in figure 3 (C).

And step D, using a metal organic chemical vapor deposition technology, setting the process conditions of 1200 ℃ of temperature, 40Torr of pressure, 2000sccm of ammonia gas flow, 90sccm of gallium source flow and 3000sccm of hydrogen gas flow, and depositing a GaN buffer layer with the thickness of 3000nm on the AlN nucleating layer, as shown in figure 3 (D).

Step E, using molecular beam epitaxy method, at 720 deg.C, the equilibrium vapor pressure of gallium beam is 7.5 × 10^{- 7}Torr and equilibrium vapor pressure of silicon beam current is 3.0X 10^-8Depositing the GaN buffer layer with the thickness of 300nm and the doping concentration of 5 multiplied by 10 under the process conditions of Torr, nitrogen flow of 2.3sccm and nitrogen plasma radio frequency source power of 375W¹⁹cm^-3N of (A) to (B)⁺And (e) a GaN emitter ohmic contact layer as shown in FIG. 3 (e).

Step F, using molecular beam epitaxy method, at 720 deg.C, the equilibrium vapor pressure of gallium beam is 7.5 × 10^{- 7}Torr, nitrogen flow rate of 2.3sccm, and nitrogen plasma RF source power of 375W under the process conditions⁺A second GaN spacer layer was deposited on the GaN emitter ohmic contact layer to a thickness of 4nm, as shown in FIG. 3 (f).

Step G, using molecular beam epitaxy method, at 720 deg.C, nitrogen flow rate of 2.3sccm, and aluminum beam equilibrium vapor pressure of 2.8 × 10^-7The equilibrium vapor pressure of Torr and gallium beam is 7.5X 10^-7Depositing a second Al layer with a thickness of 3nm and an Al component of 25% on the second GaN isolating layer under the process conditions of Torr and a nitrogen plasma radio frequency source power of 375W_0.25Ga_0.75N barrier layer, FIG. 3 (g).

Step H, using molecular beam epitaxy method, gallium beam equivalent equilibrium vapor pressure is 7.5 multiplied by 10 at the temperature of 720 DEG C^{- 7}And (d) depositing a GaN quantum well layer with the thickness of 1nm on the second AlGaN barrier layer under the process conditions of Torr, nitrogen flow of 2.3sccm and nitrogen plasma radio frequency source power of 375W, as shown in FIG. 3 (h).

Step I, using molecular beam epitaxy method, at 720 deg.C, nitrogen flow rate of 2.3sccm, and aluminum beam equilibrium vapor pressure of 2.8 × 10^-7The equilibrium vapor pressure of Torr and gallium beam is 7.5X 10^-7Torr, nitrogen, etcDepositing first Al with the thickness of 3nm and the Al component of 25% on the GaN quantum well layer under the process condition that the power of the plasma radio frequency source is 375W_0.25Ga_0.75And (e) an N barrier layer, as shown in FIG. 3 (i).

Step J, using molecular beam epitaxy method, at 720 deg.C, the equilibrium vapor pressure of gallium beam is 7.5 × 10^{- 7}A first GaN spacer layer was deposited on the first AlGaN barrier layer to a thickness of 4nm under process conditions of Torr, nitrogen flow of 2.3sccm, and nitrogen plasma RF source power of 375W, as shown in FIG. 3 (j).

Step K, using molecular beam epitaxy method, at 720 deg.C, the equilibrium vapor pressure of gallium beam is 7.5 × 10^{- 7}Torr and equilibrium vapor pressure of silicon beam current is 3.0X 10^-8Depositing 300nm thick and 5X 10 doping concentration on the first GaN isolating layer under the process conditions of Torr, nitrogen flow of 2.3sccm and nitrogen plasma radio frequency source power of 375W¹⁹cm^-3N of (A) to (B)⁺And a GaN collector ohmic contact layer as shown in FIG. 3 (k).

Step L, using metal organic chemical vapor deposition technology, setting the process conditions of 1100 ℃ of temperature, 40Torr of pressure, 2000sccm of ammonia gas flow, 120sccm of gallium source flow and 3000sccm of hydrogen gas flow at n⁺A GaN support layer with a thickness of 7 μm was deposited on the GaN collector ohmic contact layer, as shown in FIG. 3 (l).

Step M, using low pressure chemical vapor deposition technique to deposit 200nm thick SiN transition layer on the GaN support layer, as shown in FIG. 3 (M).

And step N, using a microwave plasma chemical vapor deposition technology, setting the process conditions of 1000 ℃ of temperature, 60mL/min of methane flow, 190Torr of pressure, 4.5kW of microwave power, 90 muL/min of nitrogen flow and 650mL/min of hydrogen flow, and depositing a diamond substrate with the thickness of 60 muM on the SiN transition layer, as shown in figure 3 (N).

And step O, stripping the self-supporting gallium nitride epitaxial wafer and the transfer layer, as shown in figure 3 (O).

Step P, using an etching technique, removes the nucleation layer and the buffer layer, as shown in fig. 3 (P).

Step Q, adding n⁺GaN emissionThe whole of the ohmic contact layer and the upper portion thereof is turned upside down as shown in fig. 3 (q).

After turning over, the diamond substrate, the SiN transition layer, the GaN supporting layer and n are arranged from bottom to top⁺GaN collector ohmic contact layer, first GaN isolating layer, first AlGaN barrier layer, GaN quantum well layer, second AlGaN barrier layer, second GaN isolating layer, n⁺And a GaN emitter ohmic contact layer.

Step R, at n⁺And (3) photoresist homogenizing, photoetching, developing and etching are carried out on the GaN emitter ohmic contact layer to form a grid-shaped mesa isolation with the depth of 700nm, as shown in figure 3 (r).

R1) forming mesa isolation patterns by photolithography:

the specific implementation of this step is the same as step 18a) of the first embodiment.

R2) etching to form mesa isolation: using photoresist as mask, adopting inductively coupled plasma etching method, and using Cl₂The gas flow rate was 10sccm, BCl₃Etching n under the process conditions of the gas flow of 25sccm and the etching time of 420s⁺The GaN emitter ohmic contact layer forms grid-shaped mesa isolation with the depth of 700 nm.

Step S, at n⁺Etching the ohmic contact layer of the GaN emitting electrode to n⁺A GaN collector ohmic contact layer, a cylindrical mesa having a diameter of 4 μm was formed, and metal was deposited to form an emitter electrode, as shown in fig. 3(s).

S.1) photoetching to form a circular mesa pattern:

s.1a) at n⁺And spin-coating PMMA A4 photoresist on the GaN emitter ohmic contact layer: firstly, the rotation speed is 500rad/min, the acceleration is 1000rad^2/Spin coating for 3s at min; then the rotation speed is 4000rad/min, the acceleration is 2000rad²Spin coating for 30s at min, and baking at 180 deg.C for 90 s.

S.1b) adopting an electron beam lithography method, setting an electron dose ratio to be 750, and exposing PMMA A4 photoresist;

s.1c) firstly adopting the photoresist after exposure treatment according to the proportion of 3: developing the solution of 1 tetramethyl-cyclopentanone and isopropanol for 120s, and fixing with isopropanol for 30s to form a circular mesa pattern with a diameter of 4 μm;

s2) adopting an electron beam evaporation method to form a circular mesa patternEvaporating Ti/Au/Ni metal with the thickness of 20/80/50nm at the speed of the first step, and then soaking the Ti/Au/Ni metal in an acetone solution;

s3) setting Cl by using metal as a mask and adopting an inductively coupled plasma etching method₂The gas flow rate was 10sccm, BCl₃The flow rate is 25sccm, the etching time is 150s, and n is etched⁺GaN emitter ohmic contact layer to n⁺And the GaN collector ohmic contact layer forms a cylindrical mesa with the diameter of 4 mu m.

Step T, at n⁺A ring-shaped collector electrode having an inner circumference of 3 μm from the cylindrical mesa was formed on the GaN collector ohmic contact layer as shown in fig. 3 (t).

The specific implementation of this step is the same as step twenty of the first embodiment.

Step U of depositing HfO₂Dielectric passivation layer, as shown in fig. 3 (u).

Using an atomic layer deposition process, setting the time to be 70s, the temperature to be 280 ℃, the flow of the ethylmethylamino hafnium to be 1200sccm, and H₂O flow rate of 110sccm, N₂The flow rate is 1000sccm, and HfO with the thickness of 100nm is deposited on the whole surface of the device₂A dielectric passivation layer.

Step V, in HfO₂And photoetching and etching are carried out on the dielectric passivation layer to form a collector electrode through hole, as shown in figure 3 (v).

V1) lithography to form collector electrode via pattern:

the specific implementation of this step is the same as step 22a) of the first embodiment.

V2) etching to form a collector electrode via: the photoresist is used as a mask, the pressure is set to be 1500mTorr, the power is set to be 200W, and the SF is set to be₆Flow rate of 8sccm, CHF₃The flow rate of He is 150sccm, and a reactive ion etching method is adopted to etch HfO₂And a medium passivation layer is coated on the metal surface of the collector electrode to form a collector electrode through hole.

Step W in HfO₂Preparing diameter on the medium passivation layerIs a3 μm emitter electrode via, as shown in fig. 3 (w).

W1) forming an emitter electrode through hole pattern by photoetching:

the specific implementation of this step is the same as step 23a) of the first embodiment.

W.2) etching to form an emitter electrode through hole: the photoresist is used as a mask, the pressure is set to be 1500mTorr, the power is set to be 200W, and the SF is set to be₆Flow rate of 8sccm, CHF₃Etching HfO by reactive ion etching under the process conditions of 10sccm and 150sccm of He flow₂And (4) a medium passivation layer is coated on the metal surface of the emitter electrode to form an emitter electrode through hole with the diameter of 3 mu m.

And step X, leading out an emitter electrode Pad and a collector electrode Pad on the emitter through hole and the collector through hole, as shown in figure 3 (X).

The specific implementation of this step is the same as twenty-four steps of the first embodiment.

The foregoing description is only exemplary of the invention and is not intended to limit the invention, and it will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the principles and arrangements of the invention, but such changes and modifications are within the scope of the invention as defined in the appended claims.