Highly reliable AlGaN / GaN HEMT and method for manufacturing the same

Abstract

The application relates to a high-reliability AlGaN / GaN HEMT and a preparation method thereof, which comprises a SiC substrate, an n-SiC epitaxial layer, a GaN buffer layer, an AlN insertion layer, an AlGaN barrier layer and a P-GaN cap layer, an active electrode, a drain electrode and a Schottky contact metal gate electrode are prepared above the P-GaN cap layer; a Schottky contact metal electrode, an n + type SiC ion implantation region and an ohmic contact metal electrode are further prepared on the n-SiC epitaxial layer; the AlGaN / GaN HEMT drain electrode is connected with the SiC SBD ohmic contact electrode, the AlGaN / GaN HEMT source electrode is connected with the SiC SBD Schottky contact electrode, and on-chip integration is formed. After the SiC SBD and the AlGaN / GaN HEMT are integrated, the AlGaN / GaN HEMT has the performance advantages of high reliability, high breakdown voltage, high integration degree, good heat dissipation performance and the like.

Description

TECHNICAL FIELD

[0001] The application relates to a high-reliability AlGaN / GaN HEMT and a preparation method thereof, and belongs to the technical field of microelectronics. BACKGROUND

[0002] In order to cope with the increasingly serious global warming problem and achieve the goal of carbon neutrality, power devices need further technical innovation, and power converters must be more efficient, smaller and more reliable than the current ones. When power transistors are used as switches in power conversion modules, three performance improvements are required: (1) low on-resistance; (2) high switching speed; (3) non-destructive breakdown capability. For mainstream silicon transistors, these three performances have almost reached the material limit, while wide-bandgap semiconductors represented by gallium nitride (GaN) have wide bandgaps, high saturation drift speed, large critical breakdown field, and radiation resistance. The GaN high electron mobility transistor (HEMT) is particularly suitable for high-power, high-speed, low-loss power switching modules and circuits, and has broad application prospects in photovoltaic inverters, consumer electronic product power supplies, telecommunications and data communications, electric vehicles, etc.

[0003] In practical applications, the traditional Si MOSFET has a reverse diode in series due to doping. During the breakdown process of the device, the diode is first broken down, and the breakdown of the diode is recoverable, so that the device can still be repeatedly used after breakdown, thereby improving the reliability of the Si MOSFET. The GaN HEMT is based on an undoped Al(Ga, In)N / GaN heterostructure system, and there is no PN junction between the source and the drain, and no body diode, resulting in poor avalanche capability. When the drain voltage exceeds the rated voltage of the device in the blocking state, the device will be irreparably damaged, which will cause safety and reliability problems of the device itself and the system, causing great inconvenience in practical applications. If a reverse Schottky diode (SBD) is connected in parallel, the breakdown voltage of the diode is lower than that of the GaN HEMT. At a large voltage, the diode is first broken down to protect the GaN HEMT from being damaged, thereby effectively improving the reliability of the device. The existing structure connects the GaN HEMT and the SiCSBD chip externally to realize the breakdown protection of the GaN HEMT device, which not only increases the overall size of the device module, but also increases the power consumption of the device due to the external connection, resulting in parasitic factors and noise effects. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a high-reliability AlGaN / GaN HEMT and a preparation method thereof, wherein a SiC SBD and an AlGaN / GaN HEMT are prepared on the same SiC substrate, and they are reversely connected in series, so as to protect the GaN from breakdown, thereby making the prepared AlGaN / GaN HEMT have the advantages of high reliability, high breakdown voltage, high integration degree, good heat dissipation performance and the like.

[0005] The technical scheme of the application is:

[0006] A high-reliability AlGaN / GaN HEMT comprises a SiC substrate and an n-SiC epitaxial layer grown on the SiC substrate, wherein a GaN buffer layer, an AlN insertion layer and an AlGaN barrier layer are sequentially grown on the n-SiC epitaxial layer, and the GaN buffer layer, the AlN insertion layer and the AlGaN barrier layer form a heterojunction; a p-GaN cap layer is grown on the AlGaN barrier layer, and an AlGaN / GaN HEMT ohmic contact metal source and an ohmic contact metal drain are prepared on both sides of the p-GaN cap layer, and an AlGaN / GaN HEMT Schottky contact metal gate is arranged above the p-GaN cap layer; an n + type SiC ion implantation region and a SiC SBD Schottky contact metal electrode are further prepared on the n + type SiC ion implantation region; an AlGaN / GaN HEMT ohmic contact drain is connected with the SiC SBD ohmic contact metal electrode, and an AlGaN / GaN HEMT ohmic contact source is connected with the SiC SBD Schottky contact metal electrode, so as to realize on-chip integration of the AlGaN / GaN HEMT and the SiC SBD device.

[0007] Since there is no PN junction between the source and the drain of the AlGaN / GaN HEMT, the AlGaN / GaN HEMT has no body diode, and thus has poor avalanche capability. When the drain voltage exceeds the rated withstand voltage of the device in the blocking state, the safety and reliability of the device itself and the system are affected, which causes great inconvenience in practical application. The SiC SBD has high breakdown voltage and non-destructive breakdown capability, so that the on-chip integration of the AlGaN / GaN HEMT and the SiC SBD not only can greatly reduce the size of the device, but also can design the breakdown voltage of the SiC SBD to be slightly lower than that of the AlGaN / GaN HEMT, so that the HEMT device has stable and reversible breakdown performance. In addition, since SiC is selected as the substrate of the integrated device, the excellent heat dissipation characteristics of SiC can also improve the conversion efficiency and reliability of the device.

[0008] According to the application, the n +The ion doping concentration of the SiC ion implantation area is 5×10 18 -5×10 19 cm -3 ;n + The thickness of the SiC ion implantation region is 0.2-0.5 μm.

[0009] Further preferably, n + The ion doping concentration of the SiC ion implantation area is 2×10 19 cm -3 ,n + The thickness of the SiC ion implantation region is 0.3 μm.

[0010] Preparation + The role of the SiC ion implantation region is to form the SiC SBD ohmic contact. + If the doping concentration of the SiC ion implanted region is too low, the ohmic contact resistance will be too large or even difficult to form an ohmic contact, which will result in too low a forward conduction current of the SiC SBD; if the doping concentration is too high, the number of implantations will increase, which will place higher requirements on the implantation equipment and increase the process cost. + If the thickness of the SiC ion implantation region is too large, the breakdown voltage of the SiC SBD will be too low. If the thickness of the SiC ion implantation region is too small, the ohmic contact resistance will be too large or even difficult to form ohmic contact, resulting in too low forward conduction current of the SiC SBD.

[0011] According to the preferred embodiment of the present invention, the doping concentration of the n-SiC epitaxial layer is 1×10 15 -1×10 17 cm -3 ;The thickness of the n-SiC epitaxial layer is 5-15μm;

[0012] Further preferably, the doping concentration of the n-SiC epitaxial layer is 1×10 16 cm -3 ;The thickness of the n-SiC epitaxial layer is 9μm.

[0013] If the thickness of the n-SiC epitaxial layer is too large, the breakdown voltage of the SiC SBD will be higher than that of the AlGaN / GaN HEMT, and device breakdown protection cannot be achieved; if the thickness of the n-SiC epitaxial layer is too small, the breakdown voltage of the SiC SBD will be too low, reducing the breakdown voltage characteristics of the overall device.

[0014] If the doping concentration of the n-SiC epitaxial layer is too high, the breakdown voltage of the SiC SBD will be low, reducing the breakdown voltage characteristics of the overall device; if the doping concentration of the n-SiC epitaxial layer is too low, the on-resistance of the SiC SBD will be large, resulting in the breakdown voltage of the SiC SBD being higher than that of AlGaN / GaNHEMT, and the device breakdown protection cannot be achieved.

[0015] Preferably, the material of the SiC SBD ohmic contact metal electrode is Ni metal, Ni / Ti metal stack or Ti / Ni metal stack;

[0016] The material of the SiC SBD Schottky contact metal electrode is Ti metal, Ti / Al metal stack or Mo / Al metal stack;

[0017] The material of the AlGaN / GaN HEMT ohmic contact metal source and the AlGaN / GaN HEMT ohmic contact metal drain is Ti / Al / Ni / Au metal stack, Ti / Al / Ti / Au metal stack or Ti / Al / Mo / Au metal stack;

[0018] The material of the AlGaN / GaN HEMT Schottky contact metal gate is Ni / Au metal stack, Pt / Au alloy or Pd / Au metal stack;

[0019] Further preferably, the material of the SiC SBD ohmic contact metal electrode is Ni metal, the material of the SiC SBD Schottky contact metal electrode is Ti / Al metal stack, the material of the AlGaN / GaN HEMT ohmic contact metal source and the ohmic contact metal drain is Ti / Al / Ni / Au metal stack, and the material of the AlGaN / GaN HEMT Schottky contact metal gate is Ni / Au metal stack.

[0020] Based on the relatively mature SiC SBD and AlGaN / GaN HEMT electrode processes, and considering the annealing conditions of the electrodes of the two devices, the Ni ohmic contact metal electrode and the Ti / Al Schottky contact metal electrode are selected on the SiC SBD, the Ti / Al / Ni / Au ohmic contact metal electrode and the Ni / Au Schottky contact metal electrode are selected on the AlGaN / GaN HEMT. Selecting appropriate ohmic contact metal electrodes and annealing conditions can reduce the on-resistance of the device and improve the output current of the device. Selecting appropriate Schottky contact metal electrodes can improve the barrier height of the device and reduce the leakage performance of the Schottky contact.

[0021] Preferably, the GaN buffer layer is an unintentionally doped GaN buffer layer or a doped high-resistance GaN buffer layer, and the thickness of the GaN buffer layer is 1-3 μm.

[0022] The thickness of the AlN insertion layer is 0.5-1.5 nm.

[0023] The molar ratio of Al component in the AlGaN barrier layer is 0.15-0.25, and the thickness of the AlGaN barrier layer is 15-25 nm.

[0024] The doping concentration of the p-GaN cap layer is 1x10 18 -1x10 20 cm -3 The thickness of the p-GaN cap layer is 60-100nm.

[0025] Further preferably, the GaN buffer layer is an unintentionally doped GaN buffer layer, and the thickness of the GaN buffer layer is 2pm.

[0026] The thickness of the AlN interlayer is 1nm.

[0027] The molar ratio of Al component in the AlGaN barrier layer is 0.2, and the thickness of the AlGaN barrier layer is 20nm.

[0028] The doping concentration of the p-GaN cap layer is 1x10 19 cm -3 The thickness of the p-GaN cap layer is 70nm.

[0029] The preparation method of the high-reliability AlGaN / GaN HEMT above comprises the following steps:

[0030] S1, growing an n-SiC epitaxial layer on a SiC substrate;

[0031] S2, preparing an n + -type SiC ion implantation region in a specific region of the n-SiC epitaxial layer, and performing high-temperature annealing;

[0032] S3, growing a GaN buffer layer, an AlN interlayer, and an AlGaN barrier layer in sequence on the other side of the n-SiC epitaxial layer; the position of the growth of the GaN buffer layer is different from the position of the n + -type SiC ion implantation region in the n-SiC epitaxial layer.

[0033] S4, growing a p-GaN cap layer on the AlGaN barrier layer;

[0034] S5, removing the p-GaN cap layer outside the AlGaN / GaN HEMT Schottky contact metal gate region by a dry etching method;

[0035] S6, evaporating a SiC SBD ohmic contact metal electrode on the n + -type SiC ion implantation region prepared in step S2, and performing annealing treatment;

[0036] S7, forming an AlGaN / GaN HEMT ohmic contact metal source and drain by metal evaporation and annealing treatment on the AlGaN barrier layer;

[0037] S8, evaporating SiC SBD Schottky contact metal electrode on the n-SiC epitaxial layer;

[0038] S9, evaporating AlGaN / GaN HEMT Schottky contact metal gate on the p-GaN cap layer;

[0039] S10, connecting the AlGaN / GaN HEMT ohmic contact metal drain and the SiC SBD ohmic contact metal electrode prepared on the n-SiC epitaxial layer by depositing metal;

[0040] S11, leading out the AlGaN / GaN HEMT Schottky contact metal gate electrode;

[0041] S12, connecting the AlGaN / GaN HEMT ohmic contact metal source and the SiC SBD Schottky contact metal electrode prepared on the n-SiC epitaxial layer by depositing metal.

[0042] According to the application, preferably, in step S2, the n + type SiC ion implantation region is prepared on the n-SiC epitaxial layer by ion implantation technology.

[0043] According to the application, preferably, in steps S3 and S4, the GaN buffer layer, the AlN insertion layer, the AlGaN barrier layer and the p-GaN cap layer are grown by metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0044] According to the application, preferably, in steps S3 and S4, the GaN buffer layer, the AlN insertion layer, the AlGaN barrier layer and the p-GaN cap layer are grown by metal organic chemical vapor deposition (MOCVD), which specifically comprises the following steps:

[0045] S3-1, depositing a mask layer on the n-SiC epitaxial layer;

[0046] S3-2, exposing the metal organic chemical vapor deposition growth area by using a photoetching development technology on the mask layer;

[0047] S3-3, removing the mask layer of the metal organic chemical vapor deposition growth area and retaining the mask layer of other areas, so as to realize the patterning of the mask layer;

[0048] S3-4, sequentially growing the GaN buffer layer, the AlN insertion layer, the AlGaN barrier layer and the p-GaN cap layer by using a metal organic chemical vapor deposition device, so as to form a p-GaN / AlGaN / AlN / GaN heterojunction;

[0049] S3-4, removing the mask layer and the heterojunction above the mask layer by using a stripping process.

[0050] According to the application, preferably, in step S5, the p-GaN cap layer is etched by inductively coupled plasma etching (ICP) or reactive ion etching (RIE).

[0051] According to the application, preferably, the specific process of etching the p-GaN cap layer by inductively coupled plasma etching (ICP) is as follows:

[0052] S5-1, coating photoresist on the p-GaN cap layer;

[0053] S5-2, exposing the p-GaN area to be etched on the photoresist by using photoetching development technology;

[0054] S5-3, etching the p-GaN by using inductively coupled plasma device;

[0055] S5-4, removing the coated photoresist, so that the p-GaN cap layer only exists under the AlGaN / GaN HEMT Schottky contact metal gate.

[0056] The application has the following advantages:

[0057] 1. High reliability. Generally, GaN transistors are easy to be broken down, but after being integrated with SiC SBD, by designing the breakdown voltage of SiC SBD to be slightly lower than that of AlGaN / GaN HEMT, the AlGaN / GaN HEMT can obtain the non-destructive avalanche breakdown performance in SiC diode, thereby improving the reliability of AlGaN / GaN HEMT.

[0058] 2. High breakdown voltage. The thick and low-concentration n-SiC epitaxial layer can effectively suppress the substrate leakage of AlGaN / GaN HEMT device and improve the breakdown voltage.

[0059] 3. Better heat dissipation performance. Since the thermal conductivity of SiC is three times that of Si, the presence of SiC substrate and n-SiC improves the heat dissipation performance of the device.

[0060] 4. High integration. Compared with external lead connection of chips, on-chip integration greatly reduces the size of the device and improves the integration of the device, further promoting the miniaturization of GaN power devices. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 is a structural schematic diagram of the structure obtained after step S1.

[0062] Figure 2 is a structural schematic diagram of the structure obtained after step S2.

[0063] Figure 3 is a structural schematic diagram of the structure obtained after step S3.

[0064] Figure 4 is a structural schematic diagram obtained after step S4.

[0065] Figure 5 is a structural schematic diagram obtained after step S5.

[0066] Figure 6 is a structural schematic diagram obtained after step S6.

[0067] Figure 7 is a structural schematic diagram obtained after step S7.

[0068] Figure 8 is a structural schematic diagram obtained after step S8.

[0069] Figure 9 is a structural schematic diagram obtained after step S9.

[0070] Figure 10 is a structural schematic diagram obtained after step S10.

[0071] Figure 11 is a structural schematic diagram obtained after step S11.

[0072] Figure 12 is a structural schematic diagram obtained after step S12.

[0073] Figure 13 is a device circuit schematic diagram of a high-reliability AlGaN / GaN HEMT provided by the present application.

[0074] 1, SiC substrate, 2, n-SiC epitaxial layer, 3, n + type SiC ion implantation region, 4, GaN buffer layer, 5, AlN insertion layer, 6, AlGaN barrier layer, 7, p-GaN cap layer, 8, SiC SBD ohmic contact metal electrode, 9, AlGaN / GaN HEMT ohmic contact metal source, 10, AlGaN / GaN HEMT ohmic contact metal drain, 11, SiC SBD Schottky contact metal electrode, 12, AlGaN / GaN HEMT Schottky contact metal gate. DETAILED DESCRIPTION

[0075] The present application will be further described below in conjunction with examples and the accompanying drawings of the specification, but is not limited thereto.

[0076] Example 1

[0077] A high-reliability AlGaN / GaN HEMT, such as Figure 12As shown, including SiC substrate 1 and n-SiC epitaxial layer 2 grown on SiC substrate 1, n-SiC epitaxial layer 2 has GaN buffer layer 4, AlN interlayer 5 and AlGaN barrier layer 6 grown in turn, GaN buffer layer 4, AlN interlayer 5 and AlGaN barrier layer 6 form a heterojunction; AlGaN barrier layer 6 has p-GaN cap layer 7 grown thereon, AlGaN / GaN HEMT ohmic contact metal source 9 and AlGaN / GaN HEMT ohmic contact metal drain 10 are prepared on both sides of p-GaN cap layer 7, and AlGaN / GaN HEMT Schottky contact metal gate 12 is prepared above p-GaN cap layer 7; n-SiC epitaxial layer 2 also has n + type SiC ion implantation region 3 and SiC SBD Schottky contact metal electrode 11, n + SiC SBD ohmic contact metal electrode 8 is prepared on n + type SiC ion implantation region 3, GaN buffer layer 4 and SiC SBD Schottky contact metal electrode 11 are all prepared on different regions of n-SiC epitaxial layer 2. The device circuit schematic diagram of AlGaN / GaN HEMT is shown in Figure 13

[0078] Since there is no PN junction between the source and drain of AlGaN / GaN HEMT, AlGaN / GaN HEMT has no body diode, so its avalanche capability is poor. In the blocking state, when the drain voltage exceeds the rated withstand voltage of the device, it will cause safety and reliability problems of the device itself and the system, which causes great inconvenience to practical application. SiC SBD has high breakdown voltage and non-destructive breakdown capability, therefore, monolithic integration of AlGaN / GaN HEMT and SiC SBD not only can greatly reduce the size of the device, but also can design the breakdown voltage of SiC SBD to be slightly lower than that of AlGaN / GaN HEMT, so that the HEMT device has stable and reversible breakdown performance. And because SiC is selected as the substrate of the integrated device, its excellent heat dissipation characteristics can also improve the conversion efficiency and reliability of the device.

[0079] Embodiment 2

[0080] According to the high-reliability AlGaN / GaN HEMT provided in embodiment 1, the difference lies in that:

[0081] n + ​The ion doping concentration of the SiC ion implantation region 3 is 5×10 18 -5×10 19 cm -3 ;n + The thickness of the SiC ion implantation region 3 is 0.2-0.5 μm.

[0082] Preparation + The role of the SiC ion implantation region 3 is to form an ohmic contact with the SiC SBD. + If the doping concentration of the SiC ion implantation region 3 is too low, the ohmic contact resistance will be too large or even difficult to form an ohmic contact, which will lead to a too low forward current of the SiC SBD. If the doping concentration is too high, the number of implantations will increase, which will place higher requirements on the implantation equipment and increase the process cost. + If the thickness of the SiC ion implantation region is too large, the breakdown voltage of the SiC SBD will be too low. If the thickness is too small, the ohmic contact resistance will be too large or even difficult to form an ohmic contact, resulting in a too low forward conduction current of the SiC SBD. + If the thickness of the n-SiC ion implantation region 3 is too large, the breakdown voltage of the SiC SBD will be too low, while if it is too small, the on-resistance of the SiC SBD will be too high. The doping concentration of the n-SiC epitaxial layer 2 is 1×10 15 -1×10 17 cm -3 ; The thickness of the n-SiC epitaxial layer 2 is 5-15 μm;

[0083] If the thickness of the n-SiC epitaxial layer 2 is too large, the breakdown voltage of the SiC SBD will be higher than that of the AlGaN / GaN HEMT, and the device breakdown protection cannot be achieved. If the thickness of the n-SiC epitaxial layer 2 is too small, the breakdown voltage of the SiC SBD will be too low, which will reduce the breakdown voltage characteristics of the entire device.

[0084] If the doping concentration of the n-SiC epitaxial layer 2 is too high, the breakdown voltage of the SiC SBD will be low, reducing the breakdown voltage characteristics of the entire device; if the doping concentration of the n-SiC epitaxial layer 2 is too low, the on-resistance of the SiC SBD will be large, resulting in the breakdown voltage of the SiC SBD being higher than that of the AlGaN / GaN HEMT, and the device breakdown protection cannot be achieved.

[0085] The material of the SiC SBD ohmic contact metal electrode 8 is Ni metal, Ni / Ti metal stack or Ti / Ni metal stack;

[0086] The material of the SiC SBD Schottky contact metal electrode 11 is Ti metal, Ti / Al metal stack or Mo / Al metal stack;

[0087] The material of the AlGaN / GaN HEMT ohmic contact metal source 9 and the AlGaN / GaN HEMT ohmic contact metal drain 10 is a Ti / Al / Ni / Au metal stack, a Ti / Al / Ti / Au metal stack or a Ti / Al / Mo / Au metal stack; wherein the metal stack is a layer structure arranged in sequence, such as the Ti / Al / Ni / Au metal stack is a Ti metal layer, an Al metal layer, a Ni metal layer and an Au metal layer grown in sequence;

[0088] The material of the AlGaN / GaN HEMT Schottky contact metal gate 12 is a Ni / Au metal stack, a Pt / Au metal stack or a Pd / Au metal stack;

[0089] The GaN buffer layer 4 is a non-intentionally doped GaN buffer layer 4 or a doped high-resistance GaN buffer layer 4; the thickness of the GaN buffer layer 4 is 1-3 μm;

[0090] The thickness of the AlN insertion layer 5 is 0.5-1.5 nm;

[0091] The molar ratio of Al component in the AlGaN barrier layer 6 is 0.15-0.25; the thickness of the AlGaN barrier layer 6 is 15-25 nm;

[0092] The doping concentration of the p-GaN cap layer 7 is 1×10 18 cm 20 -1×10 -3 -2; the thickness of the p-GaN cap layer 7 is 60-100 nm.

[0093] Embodiment 3

[0094] According to the high-reliability AlGaN / GaN HEMT provided in Embodiment 1, the difference lies in that:

[0095] The doping concentration of the n-SiC epitaxial layer 2 is 1×10 16 cm -3 -2; the thickness of the n-SiC epitaxial layer 2 is 9 μm.

[0096] The ion doping concentration of the n + -type SiC ion implantation region 3 is 2×10 19 cm -3 -2; the thickness of the n + -type SiC ion implantation region 3 is 0.3 μm.

[0097] The material of the SiC SBD ohmic contact metal electrode 8 is Ni metal; the material of the SiC SBD Schottky contact metal electrode 11 is Ti / Al metal; the material of the AlGaN / GaN HEMT ohmic contact metal source 9 and the AlGaN / GaN HEMT ohmic contact metal drain 10 is a Ti / Al / Ni / Au metal stack; the material of the AlGaN / GaN HEMT Schottky contact metal gate 12 is a Ni / Au metal stack.

[0098] Based on the currently mature SiC SBD and AlGaN / GaN HEMT electrode processes, and considering the annealing conditions for the electrodes of both devices, a Ni ohmic contact metal electrode 8 and a Ti / Al Schottky contact metal electrode 11 were selected for the SiC SBD. A Ti / Al / Ni / Au metal stack was selected as the AlGaN / GaN HEMT ohmic contact metal source 9 and AlGaN / GaN HEMT ohmic contact metal drain 10 on the AlGaN / GaN HEMT. A Ni / Au metal stack was selected as the AlGaN / GaN HEMT Schottky contact metal gate 12 on the AlGaN / GaN HEMT. Selecting the appropriate SiC SBD ohmic contact metal electrode 8 and annealing conditions can reduce the device's on-resistance, thereby increasing its output current. Selecting the appropriate Schottky contact metal electrodes (including the SiC SBD Schottky contact metal electrode 11 and the AlGaN / GaN HEMT Schottky contact metal gate 12) can increase the device's Schottky barrier height and reduce Schottky leakage.

[0099] The GaN buffer layer 4 is a non-intentionally doped GaN buffer layer 4, and the thickness of the GaN buffer layer 4 is 2 μm;

[0100] The thickness of the AlN insertion layer 5 is 1 nm;

[0101] The molar ratio of the Al component in the AlGaN barrier layer 6 is 0.2, and the thickness of the AlGaN barrier layer 6 is 20 nm;

[0102] The doping concentration of the p-GaN cap layer 7 is 1×10 19 cm -3 , the thickness of the p-GaN cap layer 7 is 70 nm.

[0103] Example 4

[0104] Embodiments 1-3 provide a method for preparing a high-reliability AlGaN / GaN HEMT, comprising the following steps:

[0105] S1, such as Figure 1 As shown, an n-SiC epitaxial layer 2 is grown on a SiC substrate 1;

[0106] S2, such as Figure 2 As shown, n-SiC epitaxial layer 2 is prepared in part of the region + Type SiC ion implantation area 3;

[0107] In step S2, n-SiC epitaxial layer 2 is prepared by ion implantation technology. + Type SiC ion implantation area 3.

[0108] S3, such as Figure 3 As shown, a GaN buffer layer 4, an AlN insertion layer 5, and an AlGaN barrier layer 6 are sequentially grown on the other side of the n-SiC epitaxial layer 2; the position where the GaN buffer layer 4 grows is the same as that of the n-SiC epitaxial layer 2. + The n-SiC ion implantation regions 3 are located at different positions in the n-SiC epitaxial layer 2 .

[0109] S4, such as Figure 4 As shown, a p-GaN cap layer 7 is grown on the AlGaN barrier layer 6 .

[0110] In steps S3 and S4 , the GaN buffer layer 4 , the AlN insertion layer 5 , the AlGaN barrier layer 6 and the p-GaN cap layer 7 are grown by metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0111] Among them, in steps S3 and S4, the GaN buffer layer 4, the AlN insertion layer 5, the AlGaN barrier layer 6 and the p-GaN cap layer 7 are grown by metal organic chemical vapor deposition (MOCVD), which specifically includes the following steps:

[0112] S3-1, depositing a mask layer on the n-SiC epitaxial layer 2;

[0113] S3-2, using photolithography and development technology on the mask layer to reveal the metal organic chemical vapor deposition growth area;

[0114] S3-3, removing the mask layer in the metal organic chemical vapor deposition growth area, retaining the mask layer in other areas, and achieving patterning of the mask layer;

[0115] S3-4, using a metal organic chemical vapor deposition device to sequentially grow a GaN buffer layer 4, an AlN insertion layer 5, an AlGaN barrier layer 6, and a p-GaN cap layer 7 to form an AlGaN / AlN / GaN heterojunction;

[0116] S3-4. Remove the mask layer and the heterojunction thereon using a stripping process.

[0117] S5, such as Figure 5As shown, the p-GaN cap layer 7 outside the AlGaN / GaN HEMT Schottky contact metal gate region is removed by dry etching. In this embodiment, the p-GaN cap layer 7 is etched by inductively coupled plasma etching (ICP) or reactive ion etching (RIE).

[0118] The specific process of etching the p-GaN cap layer 7 using inductively coupled plasma (ICP) etching is as follows:

[0119] S5-1, coating a photoresist on the p-GaN cap layer 7;

[0120] S5-2, using photolithography and development technology to reveal the p-GaN area to be etched on the photoresist;

[0121] S5-3, etching p-GaN using an inductively coupled plasma device;

[0122] S5-4, removing the coated photoresist, so that the p-GaN cap layer 7 exists only below the AlGaN / GaN HEMT Schottky contact metal gate 12.

[0123] S6, such as Figure 6 As shown, the n prepared in step S2 + A SiC SBD ohmic contact metal electrode 8 is evaporated on the SiC ion implantation area 3 and annealed;

[0124] S7, such as Figure 7 As shown, the AlGaN / GaN HEMT ohmic contact metal source 9 and drain 10 are formed on the AlGaN barrier layer 6 through evaporation and annealing.

[0125] S8, such as Figure 8 As shown, a SiC SBD Schottky contact metal electrode 11 is evaporated on the n-SiC epitaxial layer 2;

[0126] S9, such as Figure 9 As shown, an AlGaN / GaN HEMT Schottky contact metal gate 12 is evaporated on the p-GaN cap layer 7;

[0127] S10, such as Figure 10 As shown, the AlGaN / GaN HEMT ohmic contact metal drain 10 is connected to the SiC SBD ohmic contact metal electrode 8 prepared on the n-SiC epitaxial layer 2 by metal deposition;

[0128] S11, such as Figure 11 As shown, the AlGaN / GaN HEMT Schottky contact metal gate 12 is led out to the electrode;

[0129] S12, such as Figure 12As shown, the AlGaN / GaN HEMT ohmic contact metal source 9 and the SiC SBD Schottky contact metal electrode 11 prepared on the n-SiC epitaxial layer 2 are connected by metal deposition; it should be noted that, Figure 10 and Figure 12 Only for the schematic diagram, the specific plane interconnection is realized by directly depositing Ni / Au metal to realize the metal deposition connection.

Claims

1. A high-reliability AlGaN / GaN HEMT, characterized in that: The invention comprises a SiC substrate and an n-SiC epitaxial layer grown on the SiC substrate, wherein a GaN buffer layer, an AlN insertion layer and an AlGaN barrier layer are sequentially grown on the n-SiC epitaxial layer, and the GaN buffer layer, the AlN insertion layer and the AlGaN barrier layer form a heterojunction; a p-GaN cap layer is grown on the AlGaN barrier layer, and an AlGaN / GaN HEMT ohmic contact metal source and an ohmic contact metal drain are prepared on both sides of the p-GaN cap layer, and an AlGaN / GaNHEMT Schottky contact metal gate is above the p-GaN cap layer; an n-SiC epitaxial layer is also prepared + Type SiC ion implantation region and SiC SBD Schottky contact metal electrode, n + A SiC SBD ohmic contact metal electrode is prepared on the SiC ion implanted area; the AlGaN / GaN HEMT ohmic contact drain is connected to the SiC SBD ohmic contact metal electrode, and the AlGaN / GaN HEMT ohmic contact source is connected to the SiC SBD Schottky contact metal electrode, forming an on-wafer integration of AlGaN / GaN HEMT and SiC SBD devices.

2. The high-reliability AlGaN / GaN HEMT according to claim 1, characterized in that: n + The ion doping concentration of the SiC ion implantation area is 5×10 18 - 5×10 19 cm -3 ;n + The thickness of the SiC ion implantation region is 0.2-0.5 μm.

3. The high-reliability AlGaN / GaN HEMT according to claim 2, characterized in that: n + The ion doping concentration of the SiC ion implantation area is 2×10 19 cm -3 ;n + The thickness of the SiC ion implantation region is 0.3 μm.

4. The high-reliability AlGaN / GaN HEMT according to claim 1, wherein: The doping concentration of the n-SiC epitaxial layer is 1×10 15 -1×10 17 cm -3 ; The thickness of the n-SiC epitaxial layer is 5-15μm.

5. The high-reliability AlGaN / GaN HEMT according to claim 4, characterized in that: The doping concentration of the n-SiC epitaxial layer is 1×10 16 cm -3 ;The thickness of the n-SiC epitaxial layer is 9μm.

6. The high-reliability AlGaN / GaN HEMT according to claim 1, characterized in that: The material of the SiC SBD ohmic contact metal electrode is Ni metal, Ni / Ti metal stack or Ti / Ni metal stack; The material of the SiC SBD Schottky contact metal electrode is Ti metal, Ti / Al metal stack or Mo / Au metal stack; The materials of the AlGaN / GaN HEMT ohmic contact metal source and the AlGaN / GaN HEMT ohmic contact metal drain are Ti / Al / Ni / Au metal stack, Ti / Al / Ti / Au metal stack or Ti / Al / Mo / Au metal stack; The material of the AlGaN / GaN HEMT Schottky contact metal gate is a Ni / Au metal stack, a Pt / Al alloy, or a Pd / Au metal stack.

7. The high-reliability AlGaN / GaN HEMT according to claim 6, characterized in that: The material of the SiC SBD ohmic contact metal electrode is Ni metal; the material of the SiC SBD Schottky contact metal electrode is Ti / Al metal; the material of the AlGaN / GaNHEMT ohmic contact metal source and ohmic contact metal drain is Ti / Al / Ni / Au metal stack; the material of the AlGaN / GaNHEMT Schottky contact metal gate is Ni / Au metal stack.

8. The high-reliability AlGaN / GaN HEMT according to claim 1, characterized in that: The GaN buffer layer is an unintentionally doped GaN buffer layer or a doped GaN buffer layer; the thickness of the GaN buffer layer is 1-3 μm; The thickness of the AlN insertion layer is 0.5-1.5 nm; The molar ratio of the Al component in the AlGaN barrier layer is 0.15-0.25; the thickness of the AlGaN barrier layer is 15-25 nm; The doping concentration of the p-GaN cap layer is 1×10 18 -1×10 20 cm -3 ;The thickness of the p-GaN cap layer is 60-100nm.

9. The high-reliability AlGaN / GaN HEMT according to claim 8, characterized in that: The GaN buffer layer is a non-intentionally doped GaN buffer layer, and the thickness of the GaN buffer layer is 2 μm; The thickness of the AlN insertion layer is 1 nm; The molar ratio of the Al component in the AlGaN barrier layer is 0.2, and the thickness of the AlGaN barrier layer is 20 nm; The doping concentration of the p-GaN cap layer is 1×10 19 cm -3 , the thickness of the p-GaN cap layer is 70nm.

10. The method for preparing a high-reliability AlGaN / GaN HEMT according to any one of claims 1 to 9, characterized in that: Including steps: S1. growing an n-SiC epitaxial layer on a SiC substrate; S2. Prepare n-SiC epitaxial layer in a specific area + Type SiC ion implantation area, and annealing; S3, sequentially growing a GaN buffer layer, an AlN insertion layer, and an AlGaN barrier layer on the other side of the n-SiC epitaxial layer; S4, growing a p-GaN cap layer on the AlGaN barrier layer; S5, removing the p-GaN cap layer outside the AlGaN / GaN HEMT Schottky contact metal gate region by dry etching; S6, n prepared in step S2 + SiC SBD ohmic contact metal electrodes are evaporated on the SiC ion implanted area and annealed; S7, forming an AlGaN / GaN HEMT ohmic contact metal source and drain by evaporation and annealing on the AlGaN barrier layer; S8, evaporating a SiC SBD Schottky contact metal electrode on the n-SiC epitaxial layer; S9, evaporating an AlGaN / GaN HEMT Schottky contact metal gate on the p-GaN cap layer; S10, connecting the AlGaN / GaN HEMT ohmic contact metal drain and the SiC SBD ohmic contact metal electrode prepared on the n-SiC epitaxial layer through metal deposition; S11, connecting the AlGaN / GaN HEMT Schottky contact to the metal gate electrode; S12. Connecting the AlGaN / GaN HEMT ohmic contact metal source to the SiC SBD Schottky contact metal electrode prepared on the n-SiC epitaxial layer through metal deposition.

11. The method for preparing a high-reliability AlGaN / GaN HEMT according to claim 10, wherein: In step S2, n-SiC epitaxial layer is prepared by ion implantation technology. + Type SiC ion implantation area.

12. The method for preparing a high-reliability AlGaN / GaN HEMT according to claim 10, wherein: In steps S3 and S4, a GaN buffer layer, an AlN insertion layer, an AlGaN barrier layer and a p-GaN cap layer are grown by metal organic chemical vapor deposition or molecular beam epitaxy.

13. The method for preparing a high-reliability AlGaN / GaN HEMT according to claim 12, wherein: In steps S3 and S4, a GaN buffer layer, an AlN insertion layer, and an AlGaN barrier layer are grown using a metal organic chemical vapor deposition method, which specifically includes the following steps: S3-1, depositing a mask layer on the n-SiC epitaxial layer; S3-2, using a photolithography and development technique on the mask layer to reveal a metal organic chemical vapor deposition growth area; S3-3, removing the mask layer in the metal organic chemical vapor deposition growth area, retaining the mask layer in other areas, and achieving patterning of the mask layer; S3-4, using metal organic chemical vapor deposition equipment to sequentially grow a GaN buffer layer, an AlN insertion layer, and an AlGaN barrier layer; S4-1, growing a p-GaN cap layer on the AlGaN barrier layer to form a p-GaN / AlGaN / AlN / GaN heterojunction; S4-2. Remove the mask layer and the heterojunction thereon using a stripping process.

14. The method for preparing a high-reliability AlGaN / GaN HEMT according to claim 10, wherein: In step S5, the p-GaN cap layer is etched by inductively coupled plasma or reactive ion etching. The specific process of etching the p-GaN cap layer by inductively coupled plasma is as follows: S5-1, coating a photoresist on the p-GaN cap layer; S5-2, using photolithography and development technology to reveal the p-GaN area to be etched on the photoresist; S5-3, etching p-GaN using an inductively coupled plasma device; S5-4. Remove the coated photoresist so that the p-GaN cap layer exists only below the AlGaN / GaN HEMT Schottky contact metal gate.

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