阅读说明：本技术 一种基于氮化镓的毫米波过保护电路及其制备方法 (Millimeter wave over-protection circuit based on gallium nitride and preparation method thereof ) 是由 杨凌 马晓华 芦浩 侯斌 宓珉翰 周小伟 祝杰杰 郝跃 于 2018-11-19 设计创作，主要内容包括：本发明涉及一种基于氮化镓的毫米波过保护电路的制备方法,包括制作正向PIN二极管、反向PIN二极管和GaN基高频器件,并将正向PIN二极管和反向PIN二极管并联后通过金属互联工艺与GaN基高频器件连接,完成基于氮化镓的毫米波过保护电路的制备。本发明实施例,通过采用并联的正向PIN二极管和反向PIN二极管的电路结构,可以实现电路的自我保护；通过采用低电容材料BN,减小了栅漏寄生电容,降低了器件的频率损耗,适用于高频工作环境,满足器件能够承受正反向大功率信号的冲击。(The invention relates to a preparation method of a millimeter wave over-protection circuit based on gallium nitride, which comprises the steps of manufacturing a forward PIN diode, a reverse PIN diode and a GaN-based high-frequency device, connecting the forward PIN diode and the reverse PIN diode in parallel and then connecting the forward PIN diode and the reverse PIN diode with the GaN-based high-frequency device through a metal interconnection process, and completing the preparation of the millimeter wave over-protection circuit based on gallium nitride. According to the embodiment of the invention, the self-protection of the circuit can be realized by adopting the circuit structure of the forward PIN diode and the reverse PIN diode which are connected in parallel; by adopting the low-capacitance material BN, the grid leakage parasitic capacitance is reduced, the frequency loss of the device is reduced, the high-frequency high-power grid leakage current source is suitable for a high-frequency working environment, and the requirement that the device can bear the impact of forward and reverse high-power signals is met.)

1. A preparation method of a millimeter wave over-protection circuit based on gallium nitride is characterized by being applied to an AlGaN/GaN heterojunction, wherein the AlGaN/GaN heterojunction comprises a substrate layer, a nucleation layer, a GaN layer, a first AlGaN barrier layer and a second AlGaN barrier layer, and the method comprises the following steps:

s1, photoetching the first AlGaN barrier layer, and etching to remove the first AlGaN barrier layer;

s2, depositing a SiN medium layer on the GaN layer;

s3, forming a forward PIN diode manufacturing area and a reverse PIN diode manufacturing area on the SiN dielectric layer;

s4, manufacturing a forward PIN diode in the forward PIN diode manufacturing area;

s5, manufacturing a reverse PIN diode in the reverse PIN diode manufacturing area;

s6, manufacturing a GaN-based device on the second AlGaN barrier layer;

and S7, connecting the forward PIN diode and the reverse PIN diode in parallel and then connecting the forward PIN diode and the reverse PIN diode with the GaN-based device through metal interconnection to obtain the millimeter wave over-protection circuit based on the PIN diode.

2. The method for preparing a millimeter wave over-protection circuit based on gallium nitride according to claim 1, wherein S4 includes:

s41, photoetching a forward P + doped region in the forward PIN diode manufacturing region, etching to remove the SiN medium layer in the forward P + doped region, and carrying out P + doping in the forward P + doped region;

s42, photoetching a forward N + doped region in the forward PIN diode manufacturing region, etching to remove the SiN medium layer in the forward N + doped region, and carrying out N + doping in the forward N + doped region;

and S43, making ohmic contact in the forward P + doped region to form a forward P + region electrode, and making ohmic contact in the forward N + doped region to form a forward N + region electrode to obtain the forward PIN diode.

3. The method for preparing a millimeter wave over-protection circuit based on gallium nitride according to claim 1, wherein S5 includes:

s51, photoetching a reverse N + doped region in the reverse PIN diode manufacturing region, etching to remove the SiN dielectric layer in the reverse N + doped region, and carrying out N + doping in the reverse N + doped region;

s52, photoetching a reverse P + doped region in the reverse PIN diode manufacturing region, etching to remove the SiN dielectric layer in the reverse P + doped region, and carrying out P + doping in the reverse P + doped region;

and S53, making ohmic contact in the reverse N + doped region to form a reverse N + region electrode, and making ohmic contact in the reverse P + doped region to form a reverse P + region electrode to obtain the reverse PIN diode.

4. The method for preparing a millimeter wave over-protection circuit based on gallium nitride according to claim 1, wherein S6 includes:

s61, etching the second AlGaN barrier layer to the surface of the GaN layer;

s62, photoetching a source electrode region and a drain electrode region on the second AlGaN barrier layer, evaporating ohmic metal in the source electrode region to form a source electrode, and evaporating ohmic metal in the drain electrode region to form a drain electrode;

s63, depositing a SiN passivation layer on the second AlGaN barrier layer, and etching the SiN passivation layer;

s64, adding a BN film on the SiN passivation layer to form a composite dielectric layer;

and S65, photoetching a gate electrode region on the composite dielectric layer, etching to remove the composite dielectric layer to form a groove gate, and evaporating Schottky metal on the groove gate to form a gate.

5. The method for preparing a millimeter wave over-protection circuit based on gallium nitride according to claim 1, wherein S7 includes:

s71, depositing SiO on the positive P + region electrode, the positive N + region electrode, the reverse P + region electrode and the SiN medium layer₂A layer;

s72, depositing SiN protective layers on the source electrode, the drain electrode and the grid electrode;

s73 in the SiO₂Etching the metal interconnection layer open hole region by the SiN protective layer, and removing the SiO by etching₂The layer with the SiN protective layer carries out interconnection metal evaporation, will forward PIN diode with reverse PIN diode parallelly connected back with the grid is connected, forms the millimeter wave based on gallium nitride crosses protection circuit.

6. The method for preparing millimeter wave over-protection circuit based on gallium nitride of claim 2, wherein the doping concentration of the forward P + doping region is 1 x 10¹⁹cm^-3～1×10²⁰cm^-3The doping element is Mg, and the doping concentration of the forward N + doping area is 1 multiplied by 10¹⁶cm^-3～1×10¹⁸cm^-3The doping element is Si.

7. The method for preparing a millimeter wave over-protection circuit based on gallium nitride of claim 4, wherein the growth thickness of the SiN passivation layer is 100nm to 200nm, the etching thickness is 90nm to 190nm, and the thickness of the composite dielectric layer is 20nm to 50 nm.

8. The method for preparing a millimeter wave over-protection circuit based on gallium nitride according to claim 4, wherein the gate length of the trench gate is 0.1 μm to 0.2 μm, and the gate width is 100 μm to 1 mm.

9. The method for preparing millimeter wave over-protection circuit based on gallium nitride of claim 5, wherein the SiO is₂The thickness of the layer is 150 nm-200 nm, and the thickness of the SiN protective layer is 150 nm-200 nm.

10. A gallium nitride based millimeter wave over-protection circuit, made by the method of any of claims 1-9.

Technical Field

The invention belongs to the technical field of microelectronics, and particularly relates to a millimeter wave over-protection circuit based on gallium nitride and a preparation method thereof.

Background

Nitride semiconductor materials GaN, AlN, InN and alloys thereof are third generation wide bandgap semiconductor materials following first generation element semiconductor materials Si and Ge, second generation compound semiconductor materials GaAs and InP and the like, and have the advantages of direct band gap, wide forbidden bandwidth, large continuous modulatable range, high breakdown field strength, high saturated electron drift speed, high thermal conductivity and good radiation resistance. With the improvement of the development level of science and technology and society, the first and second generation semiconductor materials can not meet the requirements of electronic devices with higher frequency and higher power, and the electronic devices based on nitride semiconductor materials can meet the requirements, so that the device performance is greatly improved.

The monolithic microwave integrated circuit is one integrated microwave monolithic integrated circuit operating in microwave band (300MHz to 300GHz), and has the advantages of less circuit loss, low noise, wide work frequency band, etc. and may be used in reducing volume, weight and cost. Microwave monolithic integrated circuits are used as strategic development cores in many countries such as the United states and Western Europe, and a great amount of manpower and material resources are invested. Monolithic Microwave Integrated Circuits (MMICs) are widely used in many fields, military applications are mainly used in tactical missiles, electronic warfare, aviation and aerospace, and civilian applications are mainly used in satellite television, wireless communications, global positioning systems, and the like.

The front end of a radar receiver often has a high-sensitivity low-noise amplifier, and the low-noise amplifier is a small-signal linear device, which receives very weak signals, but the whole system must be capable of bearing larger power. In order to protect the devices from being burned, a microwave limiter is usually added to the front end of the receiver. When a small signal is input, the amplitude limiter only presents small loss, and when a large signal is input, the amplitude limiter greatly attenuates the small signal.

The PIN diode is a semiconductor diode which is formed by a three-layer structure, namely a P layer formed by heavily doping a P type material, an N layer formed by heavily doping an N type material, and an I layer formed by a high-resistivity lightly doped intrinsic layer sandwiched between the P layer and the N layer.

At present, GaAs MESFET amplitude limiters, GaAs Schottky barrier amplitude limiters and the like are mainly adopted at home and abroad, and the device is required to have low on-state resistance and low off-state capacitance, can bear the impact of high-power signals, and has the characteristics of small area, superior performance and the like compared with a GaAs MESFET amplitude limiter single-chip circuit.

However, the gallium arsenide second-generation semiconductor material cannot meet the requirements of electronic devices with higher frequency and higher power, and the schottky barrier limiter has insufficient capability of bearing the impact of high-power signals in the same area, so that the defect is obvious.

Therefore, how to meet the requirement that the device can bear the impact of forward and reverse high-power signals is important, and the circuit can be protected.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a millimeter wave over-protection circuit based on gallium nitride and a preparation 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 preparation method of a millimeter wave over-protection circuit based on gallium nitride, which is applied to an AlGaN/GaN heterojunction, wherein the AlGaN/GaN heterojunction comprises a substrate layer, a nucleation layer, a GaN layer, a first AlGaN barrier layer and a second AlGaN barrier layer, and the method comprises the following steps:

s1, photoetching the first AlGaN barrier layer, and etching to remove the first AlGaN barrier layer;

s2, depositing a SiN medium layer on the GaN layer;

s3, forming a forward PIN diode manufacturing area and a reverse PIN diode manufacturing area on the SiN dielectric layer;

s4, manufacturing a forward PIN diode in the forward PIN diode manufacturing area;

s5, manufacturing a reverse PIN diode in the reverse PIN diode manufacturing area;

s6, manufacturing a GaN-based device on the second AlGaN barrier layer;

and S7, connecting the forward PIN diode and the reverse PIN diode in parallel and then connecting the forward PIN diode and the reverse PIN diode with the GaN-based device through metal interconnection to obtain the millimeter wave over-protection circuit based on the PIN diode.

In one embodiment of the present invention, S4 includes:

s41, photoetching a forward P + doped region in the forward PIN diode manufacturing region, etching to remove the SiN medium layer in the forward P + doped region, and carrying out P + doping in the forward P + doped region;

s42, photoetching a forward N + doped region in the forward PIN diode manufacturing region, etching to remove the SiN medium layer in the forward N + doped region, and carrying out N + doping in the forward N + doped region;

and S43, making ohmic contact in the forward P + doped region to form a forward P + region electrode, and making ohmic contact in the forward N + doped region to form a forward N + region electrode to obtain the forward PIN diode.

In one embodiment of the present invention, S5 includes:

s51, photoetching a reverse N + doped region in the reverse PIN diode manufacturing region, etching to remove the SiN dielectric layer in the reverse N + doped region, and carrying out N + doping in the reverse N + doped region;

s52, photoetching a reverse P + doped region in the reverse PIN diode manufacturing region, etching to remove the SiN dielectric layer in the reverse P + doped region, and carrying out P + doping in the reverse P + doped region;

and S53, making ohmic contact in the reverse N + doped region to form a reverse N + region electrode, and making ohmic contact in the reverse P + doped region to form a reverse P + region electrode to obtain the reverse PIN diode.

In one embodiment of the present invention, S6 includes:

s61, etching the second AlGaN barrier layer to the surface of the GaN layer;

s62, photoetching a source electrode region and a drain electrode region on the second AlGaN barrier layer, evaporating ohmic metal in the source electrode region to form a source electrode, and evaporating ohmic metal in the drain electrode region to form a drain electrode;

s63, depositing a SiN passivation layer on the second AlGaN barrier layer, and etching the SiN passivation layer;

s64, adding a BN film on the SiN passivation layer to form a composite dielectric layer;

and S65, photoetching a gate electrode region on the composite dielectric layer, etching to remove the composite dielectric layer to form a groove gate, and evaporating Schottky metal on the groove gate to form a gate.

In one embodiment of the present invention, S7 includes:

s71, depositing SiO on the positive P + region electrode, the positive N + region electrode, the reverse P + region electrode and the SiN medium layer₂A layer;

s72, depositing SiN protective layers on the source electrode, the drain electrode and the grid electrode;

s73 in the SiO₂Etching the metal interconnection layer open hole region by the SiN protective layer, and removing the SiO by etching₂The layer with the SiN protective layer carries out interconnection metal evaporation, will forward PIN diode with reverse PIN diode parallelly connected back with the grid is connected, forms the millimeter wave based on gallium nitride crosses protection circuit.

In one embodiment of the present invention, the doping concentration of the forward P + doping region is 1 × 10¹⁹cm^-3～1×10²⁰cm^-3The doping element is Mg, and the positive N + is dopedThe doping concentration of the region is 1 × 10¹⁶cm^-3～1×10¹⁸cm^-3The doping element is Si.

In one embodiment of the invention, the growth thickness of the SiN passivation layer is 100 nm-200 nm, the etching thickness is 90 nm-190 nm, and the thickness of the composite dielectric layer is 20 nm-50 nm.

In one embodiment of the invention, the gate length of the groove gate is 0.1-0.2 μm, and the gate width is 100-1 mm.

In one embodiment of the invention, the SiO₂The thickness of the layer is 150 nm-200 nm, and the thickness of the SiN protective layer is 150 nm-200 nm.

In an embodiment of the present invention, a millimeter wave over protection circuit based on gallium nitride is prepared by the method described in the above embodiment.

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

1. the millimeter wave over-protection circuit based on the gallium nitride can realize the self-protection of the circuit by adopting the circuit structure of the forward PIN diode and the reverse PIN diode which are connected in parallel;

2. the millimeter wave over-protection circuit based on gallium nitride reduces the gate leakage parasitic capacitance and the frequency loss of the device by adopting the low-capacitance material BN, is suitable for a high-frequency working environment, and meets the requirement that the device can bear the impact of forward and reverse high-power signals.

Drawings

Fig. 1 is a schematic process flow diagram of a method for manufacturing a millimeter wave over-protection circuit based on gallium nitride according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a millimeter wave over-protection circuit based on gallium nitride according to an embodiment of the present invention;

fig. 3 is a schematic top view of a millimeter wave over-protection circuit based on gallium nitride 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.