阅读说明：本技术 p型氧化物介质复合混合阳极的肖特基二极管及制作方法 (Schottky diode with p-type oxide dielectric composite mixed anode and manufacturing method thereof ) 是由 王冲 刘凯 马晓华 郑雪峰 何云龙 郝跃 于 2021-06-29 设计创作，主要内容包括：本发明涉及一种p型氧化物介质复合混合阳极的肖特基二极管及制作方法,制作方法包括步骤：在衬底上依次生长AlGaN背势垒层、本征GaN层和AlGaN势垒层；在AlGaN势垒层表面的一端制备欧姆金属阴极,另一端制备欧姆金属阳极；在AlGaN势垒层上制备钝化层,使钝化层与欧姆金属阴极接触；在AlGaN势垒层上制备p型氧化物介质层,使p型氧化物介质层位于钝化层和欧姆金属阳极之间；在欧姆金属阳极上、p型氧化物介质层上和钝化层的部分表面上制备肖特基金属阳极。该制备方法避免采用刻蚀沟道或注入F离子工艺,不仅保证了器件的温度稳定性,而且可以精确控制p型氧化物的厚度,器件制造的可重复性高,易于制造,有利于实现大规模产业化。(The invention relates to a Schottky diode with a p-type oxide dielectric composite mixed anode and a manufacturing method thereof, wherein the manufacturing method comprises the following steps: growing an AlGaN back barrier layer, an intrinsic GaN layer and an AlGaN barrier layer on a substrate in sequence; preparing an ohmic metal cathode at one end of the surface of the AlGaN barrier layer, and preparing an ohmic metal anode at the other end of the surface of the AlGaN barrier layer; preparing a passivation layer on the AlGaN barrier layer, and enabling the passivation layer to be in contact with the ohmic metal cathode; preparing a p-type oxide dielectric layer on the AlGaN barrier layer, and enabling the p-type oxide dielectric layer to be positioned between the passivation layer and the ohmic metal anode; and preparing a Schottky metal anode on the ohmic metal anode, the p-type oxide dielectric layer and part of the surface of the passivation layer. The preparation method avoids adopting a channel etching or F ion injection process, not only ensures the temperature stability of the device, but also can accurately control the thickness of the p-type oxide, has high repeatability of device manufacture, is easy to manufacture, and is beneficial to realizing large-scale industrialization.)

1. A manufacturing method of a p-type oxide dielectric composite mixed anode Schottky diode is characterized by comprising the following steps:

growing an AlGaN back barrier layer (2), an intrinsic GaN layer (3) and an AlGaN barrier layer (4) on a substrate (1) in sequence;

preparing an ohmic metal cathode (5) at one end of the surface of the AlGaN barrier layer (4), and preparing an ohmic metal anode (6) at the other end;

preparing a passivation layer (7) on the AlGaN barrier layer (4), and enabling the passivation layer (7) to be in contact with the ohmic metal cathode (5);

preparing a p-type oxide dielectric layer (8) on the AlGaN barrier layer (4) so that the p-type oxide dielectric layer (8) is positioned between the passivation layer (7) and the ohmic metal anode (6);

preparing a Schottky metal anode (9) on the ohmic metal anode (6), the p-type oxide dielectric layer (8) and part of the surface of the passivation layer (7).

2. The method for manufacturing a p-type oxide dielectric composite mixed anode schottky diode as claimed in claim 1, wherein the AlGaN barrier layer (4) has a thickness of 5 to 15nm and an Al composition of 10 to 25%.

3. The method of claim 1, wherein the layer of p-type oxide dielectric (8) is in contact with both the passivation layer (7) and the ohmic metal anode (6).

4. The method for manufacturing the p-type oxide dielectric composite mixed anode schottky diode as claimed in claim 1, wherein the material of the p-type oxide dielectric layer (8) comprises CuO, NiO, Cu₂O、SnO、CuBO₂One or more of (a).

5. The method for manufacturing the p-type oxide dielectric composite mixed anode Schottky diode according to claim 1, wherein the thickness of the p-type oxide dielectric layer (8) is 10-50 nm.

6. A Schottky diode with a p-type oxide dielectric composite mixed anode comprises:

a substrate (1);

an AlGaN back barrier layer (2) on the substrate (1);

an intrinsic GaN layer (3) on the AlGaN back barrier layer (2);

an AlGaN barrier layer (4) on the intrinsic GaN layer (3);

an ohmic metal cathode (5) located at one end of the AlGaN barrier layer (4);

an ohmic metal anode (6) positioned at the other end of the AlGaN barrier layer (4);

a passivation layer (7) on the AlGaN barrier layer (4) and in contact with the ohmic metal cathode (5);

a p-type oxide dielectric layer (8) on the AlGaN barrier layer (4) and between the passivation layer (7) and the ohmic metal anode (6);

a Schottky metal anode (9) covering the ohmic metal anode (6) and the p-type oxide dielectric layer (8) and covering a portion of the passivation layer (7).

7. The p-type oxide dielectric composite mixed anode schottky diode as claimed in claim 6, wherein the AlGaN barrier layer (4) has a thickness of 5 to 15nm and an Al composition of 10 to 25%.

8. The p-type oxide dielectric composite mixed anode schottky diode of claim 6 wherein the p-type oxide dielectric layer (8) is in contact with both the passivation layer (7) and the ohmic metal anode (6).

9. The p-type oxide dielectric composite mixed anode schottky diode as claimed in claim 6 wherein the material of the p-type oxide dielectric layer (8) comprises CuO, NiO, Cu₂O、SnO、CuBO₂One or more of (a).

10. The p-type oxide dielectric composite mixed anode schottky diode as claimed in claim 6, wherein the thickness of the p-type oxide dielectric layer (8) is 10 to 50 nm.

Technical Field

The invention belongs to the technical field of semiconductor device structures and manufacturing, and particularly relates to a p-type oxide dielectric composite mixed anode Schottky diode and a manufacturing method thereof.

Background

Following the first generation of semiconductors represented by Si and the second generation of semiconductors represented by GaAs, the third generation of semiconductors represented by GaN has great potential for high frequency, high power applications. Compared with Si and GaAs, the GaN has the advantages of larger forbidden band width, higher carrier mobility, higher electron saturation velocity and direct band gap semiconductor, so that the GaN has wide prospect in the aspect of optical application, and the larger forbidden band width can bring larger breakdown voltage and stronger radiation resistance and high-temperature resistance. AlGaN grows on a GaN substrate, and due to polarization effect, high-concentration and high-mobility 2DEG is formed at the interface of two materials, so that various devices taking AlGaN/GaN as a base are widely researched due to the characteristic. GaN-based SBDs (schottky barrier diodes) have become one of the hot spots of research.

As early as 2008, k.takatani et al produced F-processed hybrid anode GaN-based diodes. The anode of the device is compounded by ohmic metal and Schottky metal, the ohmic metal is composed of Hf/Al/Hf/Au, F ion implantation is carried out under the Schottky metal of the anode, and the cathode is made of the ohmic metal. The mixed anode can control the on and off of the device through the Schottky metal, the depletion effect on current carriers in a channel is further enhanced through F ion injection, so that the on voltage of the diode is reduced, namely the Schottky metal and the injected F ions jointly control the switch of the device, and the current carriers flow between ohmic metals of the anode and the cathode, so that the effect of reducing the on-voltage is achieved. The turn-on voltage of the device is 0V, and the breakdown voltage exceeds 200V due to the existence of the thick AlGaN barrier layer of 30 nm. Although the device turn-on voltage is extremely low, the temperature reliability of the device is poor because the implanted F ions are not stable.

In 2015, Lee H S et al studied GaN-based diodes with a hybrid anode composite trench structure. The anode of the device is also formed by compounding ohmic metal and Schottky metal, the Schottky metal is deposited in the groove formed by etching and covers the ohmic metal, the Schottky metal is Ni/Au, and the ohmic metal is Ti/Al/Ni/Au; the authors reduce the density of the 2DEG by increasing the groove depth to achieve the desired turn-on voltage and reduce reverse leakage. When a small positive bias is applied to the anode, electrons flow from the cathode to the ohmic metal in the anode, and when a positive bias is applied to the anode that opens a schottky contact under the anode region of the recess, the electrons pass through the schottky metal, and when a negative bias is applied to the anode, the channel is depleted by the schottky metal in the recess. The additional electrons through the ohmic to ohmic path will produce high forward current and extremely low VT with less reverse leakage. The final device had a turn-on voltage of 0.34V and leakage of 1.82 μ A/mm at-15V for the anode bias. Although the turn-on voltage is reduced, etching is needed in the device manufacturing process, a large amount of damage is caused by etching, the process is complex, and the etching depth is difficult to precisely control.

In summary, if the existing GaN-based diode with the mixed anode structure is implanted with the composite F ions, the temperature stability of the device is poor because the F ions are unstable; if the hybrid anode structure composite groove gate structure is used, due to the fact that etching needs to be carried out on the device in the manufacturing process, traps exist at the interface, performance of the device is poor, meanwhile, etching depth cannot be accurately controlled, and the device is difficult to achieve on a large scale.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a p-type oxide dielectric composite mixed anode Schottky diode and a manufacturing method thereof. The technical problem to be solved by the invention is realized by the following technical scheme:

the embodiment of the invention provides a method for manufacturing a p-type oxide dielectric composite mixed anode Schottky diode, which comprises the following steps:

growing an AlGaN back barrier layer, an intrinsic GaN layer and an AlGaN barrier layer on a substrate in sequence;

preparing an ohmic metal cathode at one end of the surface of the AlGaN barrier layer, and preparing an ohmic metal anode at the other end of the surface of the AlGaN barrier layer;

preparing a passivation layer on the AlGaN barrier layer, and enabling the passivation layer to be in contact with the ohmic metal cathode;

preparing a p-type oxide dielectric layer on the AlGaN barrier layer, and enabling the p-type oxide dielectric layer to be located between the passivation layer and the ohmic metal anode;

and preparing a Schottky metal anode on the ohmic metal anode, the p-type oxide dielectric layer and part of the surface of the passivation layer.

In one embodiment of the invention, the AlGaN barrier layer has a thickness of 5-15 nm and an Al component of 10% -25%.

In one embodiment of the invention, the layer of p-type oxide dielectric is in contact with both the passivation layer and the ohmic metal anode.

In one embodiment of the invention, the material of the p-type oxide dielectric layer comprises CuO, NiO and Cu₂O、SnO、CuBO₂One or more of (a).

In one embodiment of the invention, the thickness of the p-type oxide dielectric layer is 10-50 nm.

Another embodiment of the present invention provides a schottky diode with a p-type oxide dielectric composite mixed anode, comprising:

a substrate;

an AlGaN back barrier layer on the substrate;

the intrinsic GaN layer is positioned on the AlGaN back barrier layer;

an AlGaN barrier layer on the intrinsic GaN layer;

the ohmic metal cathode is positioned at one end of the AlGaN barrier layer;

the ohmic metal anode is positioned at the other end of the AlGaN barrier layer;

a passivation layer on the AlGaN barrier layer and in contact with the ohmic metal cathode;

the p-type oxide dielectric layer is positioned on the AlGaN barrier layer and is positioned between the passivation layer and the ohmic metal anode;

and the Schottky metal anode covers the ohmic metal anode and the p-type oxide dielectric layer and covers a part of the passivation layer.

In one embodiment of the invention, the AlGaN barrier layer has a thickness of 5-15 nm and an Al component of 10% -25%.

In one embodiment of the invention, the layer of p-type oxide dielectric is in contact with both the passivation layer and the ohmic metal anode.

In one embodiment of the invention, the material of the p-type oxide dielectric layer comprises CuO, NiO and Cu₂O、SnO、CuBO₂One or more of (a).

In one embodiment of the invention, the thickness of the p-type oxide dielectric layer is 10-50 nm.

Compared with the prior art, the invention has the beneficial effects that:

1. in the manufacturing process of the Schottky diode, the p-type oxide dielectric layer is grown on the AlGaN barrier layer and between the passivation layer and the ohmic metal anode and is combined with the mixed anode formed by the ohmic metal anode and the Schottky metal anode, so that the starting voltage of the Schottky diode is reduced under the condition of not deteriorating the reverse characteristic, and meanwhile, the adoption of a channel etching process or an F ion injection process is avoided, so that the temperature stability of a device is ensured, the thickness of the p-type oxide can be accurately controlled, the manufacturing repeatability of the device is high, the manufacturing is easy, and the large-scale industrialization is favorably realized.

2. In the Schottky diode, the ohmic metal anode and the Schottky metal anode jointly form the mixed anode, and the mixed anode and the p-type oxide dielectric layer are combined, so that the turn-on voltage of the device can be reduced, and the performance of the device can be improved.

Drawings

Fig. 1 is a schematic flow chart of a method for manufacturing a p-type oxide dielectric composite mixed anode schottky diode according to an embodiment of the present invention;

fig. 2a to fig. 2i are schematic process diagrams of a method for manufacturing a p-type oxide dielectric composite mixed anode schottky diode according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a schottky diode with a p-type oxide dielectric composite mixed anode according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto.

Example one

Referring to fig. 1 and fig. 2a to fig. 2i, fig. 1 is a schematic flow chart of a method for manufacturing a p-type oxide dielectric composite mixed anode schottky diode according to an embodiment of the present invention, and fig. 2a to fig. 2i are schematic process diagrams of a method for manufacturing a p-type oxide dielectric composite mixed anode schottky diode according to an embodiment of the present invention. The manufacturing method comprises the following steps:

s1, growing AlGaN back barrier layer 2, intrinsic GaN layer 3 and AlGaN barrier layer 4 on substrate 1 in sequence, please refer to fig. 2a and 2 b.

Specifically, the material of the substrate 1 may include sapphire or SiC; an AlGaN back barrier layer 2, an intrinsic GaN layer 3, and an AlGaN barrier layer 4 may be sequentially grown on a substrate using a Metal-organic Chemical Vapor Deposition (MOCVD) process, in which a 2DEG is formed at a contact position of the intrinsic GaN layer 3 and the AlGaN barrier layer 4.

The AlGaN barrier layer 4 has a thickness of 5 to 15nm and an Al component of 10 to 25%.

S2, performing mesa isolation on the device to form an electrical isolation structure, as shown in fig. 2 c.

And etching the AlGaN barrier layer 4 and part of the intrinsic GaN layer 3 to ensure that the AlGaN barrier layer 4 and the intrinsic GaN layer 3 form a 2DEG partition, thereby realizing the mesa isolation of the device and forming an electrical isolation structure.

Specifically, firstly, a photoresist spinner is adopted to spin at the rotating speed of 3500 rpm to obtain a photoresist mask; and then, exposing by using a photoetching machine to form a mask pattern of the mesa active region. Then, the substrate with the mask is etched in Cl by an inductively coupled plasma etching machine₂The plasma carries out mesa isolation at the etching rate of 1nm/s, the etching depth is 200nm, and an electric isolation structure is formed.

S3, preparing an ohmic metal cathode 5 at one end of the surface of the AlGaN barrier layer 4, and preparing an ohmic metal anode 6 at the other end, as shown in fig. 2 d.

Specifically, firstly, photoresist is spun by a photoresist spinner at the rotating speed of 5000 r/min to obtain a photoresist mask with the thickness of 0.8 μm, then the photoresist mask is baked in a high-temperature oven at the temperature of 80 ℃ for 10min, and the photoresist is exposed by a photoetching machine to form mask patterns of cathode and anode ohmic metal areas. Then, evaporating ohmic metal on the surface of the device by adopting an electron beam evaporation table at an evaporation rate of 0.1nm/s, wherein the ohmic metal materials are Ti/Al/Ni/Au from bottom to top in sequence, the thickness of Ti can be 20nm, the thickness of Al can be 120nm, the thickness of Ni can be 45nm, and the thickness of Au can be 55 nm; and stripping the ohmic metal outside the mask patterns of the ohmic metal areas of the cathode and the anode after the ohmic contact metal is evaporated to obtain a complete ohmic metal anode and an ohmic metal cathode. Finally, the mixture is subjected to a rapid thermal annealing furnace at 870 ℃ N₂And (4) carrying out rapid thermal annealing for 30s in the atmosphere, alloying ohmic contact metal, finishing the manufacture of cathode and anode ohmic metal, and forming an ohmic metal cathode 5 and an ohmic metal anode 6. The ohmic metal cathode 5 is located at one end of the surface of the AlGaN barrier layer 4, and the ohmic metal anode 6 is located at the other end of the surface of the AlGaN barrier layer 4.

S4, preparing a passivation layer 7 on the AlGaN barrier layer 4, and bringing the passivation layer 7 into contact with the ohmic metal cathode 5.

In this embodiment, the passivation layer 7 is made of SiN.

Specifically, firstly, spin coating is carried out at a rotation speed of 5000 r/min by using a spin coater to obtain a photoresist mask with a thickness of 0.8 μmAnd m is selected. And then, baking for 10min in a high-temperature oven at the temperature of 80 ℃, and exposing the photoresist by using a photoetching machine to form a mask pattern of a passivation layer region. Then, using Plasma Enhanced Chemical Vapor Deposition (PECVD) Deposition equipment to deposit NH₃Is a source of N, SiH₄As a Si source, depositing a layer of SiN on the device surface, i.e., on the surface of the electrical isolation structure, the surface of the AlGaN barrier layer 4, the surface of the ohmic metal cathode 5, and the surface of the ohmic metal anode 6, at a temperature of 250 ℃, as shown in fig. 2e, wherein the thickness of the layer of SiN may be 100 nm; then, the passivation layer material on the surface of the electrical isolation structure, the passivation layer material on the surface of the ohmic metal cathode 5, the passivation layer material on the surface of the ohmic metal anode 6, and the SiN on the surface of the AlGaN barrier layer 4 near the ohmic metal anode 6 are removed, and a passivation layer 7 in contact with the ohmic metal cathode 5 is formed, as shown in fig. 2 f.

And S5, preparing a p-type oxide dielectric layer 8 on the AlGaN barrier layer 4, and enabling the p-type oxide dielectric layer 8 to be located between the passivation layer 7 and the ohmic metal anode 6.

Specifically, positive photoresist is thrown on the surface of the epitaxial material at the rotating speed of 5000 revolutions per minute to obtain a photoresist mask with the thickness of 0.8 mu m, the photoresist mask is baked for 10min in a high-temperature oven at the temperature of 80 ℃, and then the photoresist mask is subjected to photoetching by adopting a photoetching machine to obtain a p-type oxide dielectric region pattern. A layer of p-type oxide is then grown on the device surface using a sputtering process, as shown in figure 2 g. Finally, the p-type oxide outside the p-type oxide dielectric region is removed to form a p-type oxide dielectric layer 8, as shown in fig. 2 h.

Specifically, the material of the p-type oxide dielectric layer 8 comprises CuO, NiO and Cu₂O、SnO、CuBO₂One or more of (a). In one embodiment, 20nm of CuO is prepared on the surface of the device by a sputtering process, and then the CuO outside a p-type oxide medium area is removed to form a CuO medium layer; in another embodiment, a sputtering process is utilized to prepare a 10nm Cu metal film on the surface of the device, then oxygen is introduced into the cavity for 10min to oxidize the Cu metal film in an oxygen atmosphere to generate CuO, then the CuO outside the p-type oxide medium region is removed to form a CuO medium layer, wherein,the oxidation temperature is 300 ℃; in another embodiment, NiO with the size of 40nm is grown on the surface of the device by utilizing a sputtering process, and then the NiO outside the p-type oxide medium area is removed to form the NiO medium layer.

Further, a p-type oxide dielectric layer 8 is prepared and formed between the passivation layer 7 and the ohmic metal anode 6, and the side surface of the p-type oxide dielectric layer is in contact with the passivation layer 7 and the ohmic metal anode 6 simultaneously.

Specifically, the thickness of the p-type oxide dielectric layer 8 may be smaller than the thickness of the passivation layer 7, may also be larger than the thickness of the passivation layer 7, and may also be equal to the thickness of the passivation layer 7; similarly, the thickness of the p-type oxide dielectric layer 8 may be smaller than the thickness of the ohmic metal anode 6, may also be larger than the thickness of the ohmic metal anode 6, and may also be equal to the thickness of the ohmic metal anode 6. Since the thicker the p-type oxide dielectric layer 8, the farther the schottky metal is from the channel, the lower the control capability of the carriers in the channel, the larger the turn-on voltage of the device, and the smaller the current at the same voltage, the thickness of the p-type oxide dielectric layer 8 is smaller than that of the ohmic metal anode 6 and smaller than that of the passivation layer 7. In this embodiment, the thickness of the p-type oxide dielectric layer 8 can be precisely controlled by a sputtering process, and the repeatability of device manufacturing is high.

Specifically, the thickness of the p-type oxide dielectric layer 8 is 10-50 nm.

S6, forming a schottky metal anode 9 on the ohmic metal anode 6, the p-type oxide dielectric layer 8 and a portion of the surface of the passivation layer 7, as shown in fig. 2 i.

Firstly, spin coating with a spin coater at a rotation speed of 5000 r/min to obtain a photoresist mask with a thickness of 0.8 μm; then, baking the substrate in a high-temperature oven at the temperature of 80 ℃ for 10min, and exposing the photoresist mask by using a photoetching machine to form a Schottky metal mask pattern; finally, an electron beam evaporation table is adopted to evaporate Schottky metal on the surface of the device at an evaporation rate of 0.1nm/s, the Schottky metal is sequentially made of Ni/Au, wherein the thickness of Ni is 30nm, and the thickness of Au is 300 nm; and (4) stripping the Schottky metal except the Schottky metal mask pattern after the evaporation is finished to obtain a complete Schottky metal anode 9.

And S7, manufacturing an interconnection lead.

Firstly, throwing positive photoresist on the surface of a device by a photoresist spinner at the rotating speed of 5000 r/min; then, exposing by using a photoetching machine to form an electrode lead mask pattern; then, adopting an electron beam evaporation table to evaporate metal of a lead electrode on the surface of the substrate with the mask at an evaporation rate of 0.3nm/s, wherein the metal is Ti/Au, the thickness of Ti is 20nm, and the thickness of Au is 200 nm; and finally, stripping the lead electrode metal outside the electrode lead mask pattern to obtain a complete lead electrode.

According to the preparation method, the p-type oxide dielectric layer is grown on the AlGaN barrier layer and between the passivation layer and the ohmic metal anode and is combined with the mixed anode formed by the ohmic metal anode and the Schottky metal anode, the starting voltage of the Schottky diode is reduced under the condition that the reverse characteristic is not deteriorated, the adoption of a channel etching process or an F ion injection process is avoided, the temperature stability of a device is guaranteed, the thickness of the p-type oxide can be accurately controlled, the repeatability of device manufacturing is high, in addition, no additional complex process is needed in the device manufacturing process, the process is simple, and the large-scale industrialization is favorably realized.

Example two

On the basis of the first embodiment, please refer to fig. 3, fig. 3 is a schematic structural diagram of a schottky diode with a p-type oxide dielectric composite mixed anode according to an embodiment of the present invention, the schottky diode includes: the GaN-based semiconductor device comprises a substrate 1, an AlGaN back barrier layer 2, an intrinsic GaN layer 3, an AlGaN barrier layer 4, an ohmic metal cathode 5, an ohmic metal anode 6, a passivation layer 7, a p-type oxide dielectric layer 8 and a Schottky metal anode 9.

Specifically, the material of the substrate 1 includes sapphire or SiC.

The AlGaN back barrier layer 2 is located on the substrate 1, the intrinsic GaN layer 3 is located on the AlGaN back barrier layer 2, and the AlGaN barrier layer 4 is located on the intrinsic GaN layer 3. Wherein, 2DEG is formed at the contact position of the intrinsic GaN layer 3 and the AlGaN barrier layer 4; the AlGaN barrier layer 4 has a thickness of 5 to 15nm and an Al component of 10 to 25%.

In the embodiment, the AlGaN back barrier layer is arranged on the substrate, the energy band is improved due to the AlGaN back barrier layer, the range limitation of the device is improved, the carrier mobility is increased, meanwhile, the increased barrier height reduces electric leakage, and the breakdown voltage is improved.

An ohmic metal cathode 5 is located at one end of the AlGaN barrier layer 4, and an ohmic metal anode 6 is located at the other end of the AlGaN barrier layer 4. Specifically, the ohmic metal cathode 5 and the ohmic metal anode 6 are made of Ti/Al/Ni/Au in sequence from bottom to top, wherein the Ti thickness can be 20nm, the Al thickness can be 120nm, the Ni thickness can be 45nm, and the Au thickness can be 55 nm.

A passivation layer 7 is on the AlGaN barrier layer 4 and in contact with the ohmic metal cathode 5. Specifically, the passivation layer 7 may be SiN with a thickness of 100 nm.

A layer of p-type oxide dielectric 8 is on the AlGaN barrier layer 4 and between the passivation layer 7 and the ohmic metal anode 6.

Further, the side surface of the p-type oxide dielectric layer 8 is in contact with the passivation layer 7 and the ohmic metal anode 6 at the same time.

The thickness of the p-type oxide dielectric layer 8 can be smaller than that of the passivation layer 7, can be larger than that of the passivation layer 7, and can be equal to that of the passivation layer 7; similarly, the thickness of the p-type oxide dielectric layer 8 may be smaller than the thickness of the ohmic metal anode 6, may also be larger than the thickness of the ohmic metal anode 6, and may also be equal to the thickness of the ohmic metal anode 6. Since the thicker the p-type oxide dielectric layer 8, the farther the schottky metal is from the channel, the lower the control capability of the carriers in the channel, the larger the turn-on voltage of the device, and the smaller the current at the same voltage, the thickness of the p-type oxide dielectric layer 8 is smaller than that of the ohmic metal anode 6 and smaller than that of the passivation layer 7. In one embodiment, the thickness of the p-type oxide dielectric layer 8 is 10-50 nm.

Furthermore, the schottky diode of the embodiment can effectively regulate and control the turn-on voltage by regulating and controlling the thickness of the AlGaN barrier layer, the Al component of the AlGaN barrier layer and the thickness of the P-type oxide; when the thickness of the barrier layer and the Al component are increased, a low turn-on voltage and a high current density can be simultaneously realized by increasing the thickness of the P-type oxide.

The material of the p-type oxide dielectric layer 8 comprisesCuO、NiO、Cu₂O、SnO、CuBO₂One or more of (a).

A schottky metal anode 9 overlies the ohmic metal anode 6 and the p-type oxide dielectric layer 8 and overlies a portion of the passivation layer 7. Specifically, the material of the schottky metal anode 9 is Ni/Au sequentially from bottom to top, wherein the thickness of Ni is 30nm, and the thickness of Au is 300 nm.

In this embodiment, the ohmic metal anode 6 and the schottky metal anode 9 form a mixed anode together, and the p-type oxide dielectric layer 8 is compounded with the mixed anode, and the p-type oxide can raise the energy band of the AlGaN barrier layer 4, so that the two-dimensional electron gas at the heterojunction interface is depleted, the turn-on voltage of the schottky diode is further reduced, and the performance of the device is improved. Specifically, when no voltage is applied to the anode, carriers in a channel below the Schottky metal are depleted by utilizing the p-type oxide, and a conductive path of the device is cut off; when the anode of the diode applies forward bias, the channel is opened, the device is conducted, and the rectification characteristic of the diode is realized. Under the condition of reverse bias, the P-type oxide has the inhibiting effect similar to a PN junction on reverse current, and the reverse leakage is effectively inhibited on the premise of ensuring smaller starting voltage.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.