Gallium nitride-based epitaxial wafer, method for manufacturing the same, and power radio frequency device

Abstract

The application relates to a gallium nitride-based epitaxial wafer and a preparation method and a power radio frequency device thereof, the gallium nitride-based epitaxial wafer comprises a substrate, a buffer layer, a stress adjusting layer, a drift layer, a barrier layer and a cap layer which are arranged in a stack; the barrier layer comprises a single layer and / or a composite layer; the semiconductor material in the barrier layer comprises any one or a combination of at least two of AlN, Al x In y N or In y Al 1‑x Ga 1‑x‑y N, wherein 0.1<=x<=1 and 0<=y<=1. The gallium nitride-based epitaxial wafer provided by the application grows a barrier layer, makes the band offset in the band gap larger in a heterostructure, eliminates dislocations caused by different lattice constants between layers, slows down the reduction of the two-dimensional electron gas surface density caused by the piezoelectric polarization electric field, improves the short channel effect caused by the continuously reduced gate in the HEMT device, improves the switching speed of the device, and improves the electrical characteristics of the device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor manufacturing, and relates to a gallium nitride-based epitaxial wafer, in particular to a gallium nitride-based epitaxial wafer and a preparation method thereof and a power radio frequency device. BACKGROUND

[0002] III-V compound semiconductor materials are widely used in the fields of microelectronics and optoelectronic devices due to their wide direct band gap, good thermal and chemical stability, and have made breakthrough progress in research and application in recent years.

[0003] The third-generation semiconductor material GaN has excellent properties such as wide band gap, high critical breakdown field strength, high electron drift saturation velocity, high thermal conductivity and high electron mobility, thus having economic application prospects. At the same time, due to the strong spontaneous polarization and piezoelectric polarization effect of III-V compound semiconductors, a two-dimensional electron gas channel with high electron concentration and high mobility can be formed near the interface of the heterojunction. Therefore, GaN is particularly suitable for high-voltage, high-current, high-temperature, high-speed and high-power device applications.

[0004] CN 209626222U discloses an epitaxial layer structure of a GaN-based power semiconductor device on a Si substrate, comprising a Si substrate, a patterned structure AlN buffer layer and a GaN-based power device structure; wherein: a patterned structure is prepared on the Si substrate, the AlN buffer layer is prepared on the Si substrate with a patterned structure, and the patterned structure is cylindrical, conical, dome-shaped or polygonal prismatic. The utility model has the advantages that: by preparing a patterned structure on the Si substrate, and depositing an AlN buffer layer on the Si substrate with a patterned structure by magnetron sputtering, then growing a GaN-based power device structure on the buffer layer, the patterned structure on the Si substrate has a good effect on stress release of the epitaxial layer of the GaN-based power device structure, can reduce the dislocation density in the epitaxial layer, and improve the crystal quality; depositing an AlN buffer layer on the patterned structure Si substrate avoids the problem of Ga atom remelting, and is beneficial to subsequent epitaxial growth.

[0005] CN 207381406U discloses a GaN semiconductor device, comprising: a substrate; an aluminum nitride seed layer arranged on the substrate; a buffer layer arranged on the aluminum nitride seed layer; a gallium nitride layer arranged on the buffer layer; an Al x Ga 1-xN layer; an aluminum nitride layer disposed on the AlxGa1-xN layer; and a p-GaN layer disposed on the aluminum nitride layer. The structure of the above-mentioned GaN semiconductor device, after growing an AlGaN film for 2DEG, inserts an aluminum nitride layer before p-GaN-layer evaporation, that is, a p-GaN / AlN / AlGaN composite film or a p-GaN / AlGaN / AlN / AlGaN composite film, removes the remaining P-type gallium nitride layer left over when etching the gate in the subsequent process, and improves the spread of the p-GaN-HEMT device characteristics.

[0006] CN 113643962A discloses a preparation method of a gallium nitride epitaxial layer and a gallium nitride epitaxial wafer structure. The preparation method comprises the following steps: placing a substrate into a reaction chamber, introducing an aluminum source into the reaction chamber for a preset time to form a nucleation layer with a thickness of 2-5 nm; forming a transition layer with a total thickness of 400-450 nm on the nucleation layer, the transition layer comprising an AlGaN layer, an aluminum gradient layer and a transition GaN layer; and forming a gallium nitride epitaxial layer with a thickness of 1.5-2 microns on the transition layer. In this method, a transition layer is first deposited between the substrate and the gallium nitride epitaxial layer, and the transition layer can reduce the stress caused by lattice mismatch between the substrate and the epitaxial layer, and can prevent the wafer from warping due to lattice mismatch or stress.

[0007] The above technical solutions improve the structure of the semiconductor device and improve the performance, but do not study the two-dimensional electron gas characteristics and short channel effect characteristics, thereby improving the electrical performance of the device.

[0008] How to improve the lattice mismatch caused by the thickness of the channel layer in the epitaxial structure will lead to the reduction of the two-dimensional electron gas functional layer and the short channel effect caused by the continuous reduction of the gate, which is a technical problem to be solved in the field of semiconductor manufacturing. SUMMARY

[0009] In view of the problems in the prior art, the present application provides a gallium nitride-based epitaxial wafer and a preparation method thereof and a radio frequency power device. By setting a dislocation barrier layer, the phenomenon of larger band gap offset in the heterostructure is utilized by AlInN, which can eliminate dislocations between the dislocation barrier layer and the drift layer due to different lattice constants, and reduce the reduction of the surface density of the two-dimensional electron gas caused by the piezoelectric polarization electric field. The reduction of dislocation density, lattice matching, stronger spontaneous polarization effect and deeper triangular quantum well energy increase will enable the width of the device gate line to be reduced. The device switching frequency will increase and will not be affected by the reduction of the two-dimensional electron gas channel caused by the reduction of the gate width.

[0010] To achieve this purpose, the present application adopts the following technical solutions:

[0011] In a first aspect, the present application provides a gallium nitride-based epitaxial wafer, which comprises a substrate, a buffer layer, a stress adjustment layer, a drift layer, a barrier layer and a cap layer stacked in sequence.

[0012] The barrier layer comprises a single-layer structure and / or a composite layer structure.

[0013] The semiconductor material in the barrier layer comprises AlN, Al x In y N or In y Al 1-x Ga 1-x-y N, or a combination of at least two of them, wherein 0.1≤x≤1, 0≤y≤1.

[0014] The gallium nitride-based epitaxial wafer provided by the present application grows a barrier layer, which makes the band gap in the heterostructure larger, eliminates dislocations caused by different lattice constants between the channel layer and the stress adjustment layer, and reduces the two-dimensional electron gas surface density caused by the piezoelectric polarization electric field. Meanwhile, the short channel effect caused by the continuously reduced gate in the HEMT (High Electron Mobility Transistor) device is improved, thereby improving the high-frequency switching speed of the device and the electrical properties of the device.

[0015] The single-layer AlN or AlGaN as the barrier layer has a high energy band gap, which can reduce the easy migration of the electron wave function into the barrier layer, thereby improving the electron surface density and electron Hall mobility in the two-dimensional electron gas. The addition of In (indium) element in the AlN or AlGaN layer can reduce the piezoelectric field effect and increase the triangular quantum well energy, so that the device can still maintain a fine line width gate and increase the switching speed of the device even if the device function fails due to the reduction of the gate line width.

[0016] The AlN, AlInN or InAlGaN composite layer will maintain the single-layer effect, have a deep triangular quantum well and a low piezoelectric field effect, so that the device gate line width can be shortened and still have a high-speed switching speed.

[0017] Preferably, the barrier layer has a single-layer structure, and the semiconductor material comprises any one or a combination of at least two of AlInN, AlN or InAlGaN. A typical but non-limiting combination includes a combination of AlInN and AlN, a combination of AlN and InAlGaN, a combination of AlInN and InAlGaN, or a combination of AlInN, AlN and InAlGaN.

[0018] Preferably, the barrier layer has a composite layer structure, and the semiconductor material comprises AlN, Al x Iny N or In y Al 1-x Ga 1-x-y N or a combination of at least two of any of the foregoing, typical but non-limiting combinations include AlN and Al x In y N or a combination of Al x In y N and In y Al 1-x Ga 1-x-y N or a combination of AlN and In y Al 1-x Ga 1-x-y N or a combination of AlN, Al x In y N and In y Al 1- x Ga 1-x-y N or a combination of AlN, Al a Ga 1-a N, In c Al b Ga 1-b-c wherein 0.1 < x < 1 and 0 < y < 1.

[0019] 0.1 < x < 1, for example can be 0.1, 0.3, 0.5, 0.7, 0.9 or 1, but is not limited to the listed values, other unlisted values within the range are equally applicable.

[0020] 0 < y < 1, for example can be 0, 0.1, 0.3, 0.5, 0.7, 0.9 or 1, but is not limited to the listed values, other unlisted values within the range are equally applicable.

[0021] Preferably, the substrate comprises any of Al2O3, GaN, AlN, GaO, Si or SiC.

[0022] Preferably, the buffer layer comprises AlN and a doping material.

[0023] The doping material comprises any of carbon, beryllium, magnesium or iron or a combination of at least two of any of the foregoing, typical but non-limiting combinations include a combination of carbon and beryllium, a combination of beryllium and magnesium, a combination of magnesium and iron, a combination of carbon and magnesium, a combination of carbon and iron, a combination of beryllium and iron, a combination of carbon, beryllium and magnesium, a combination of beryllium, magnesium and iron, or a combination of carbon, beryllium, magnesium and iron.

[0024] Preferably, the stress adjustment layer comprises a single layer and / or a composite layer structure.

[0025] Preferably, the semiconductor material in the stress adjustment layer comprises AlN, GaN, AlGaN, Al a Ga 1-a N, In c Al b Ga 1-b-cN or any one or a combination of at least two of AlInGaN, typical but non-limiting combinations include a combination of AlN and GaN, GaN and AlGaN, AlGaN and Al a Ga 1-a N, a combination of Al a Ga 1-a N and In c Al b Ga 1-b-c N, a combination of In c Al b Ga 1-b-c N and AlInGaN, a combination of AlN, GaN and AlGaN, GaN, AlGaN and Al a Ga 1-a N, a combination of AlGaN, Al a Ga 1-a N and In c Al b Ga 1-b-c N, a combination of Al a Ga 1-a N, In c Al b Ga 1-b-c N and AlInGaN, a combination of AlN, GaN, AlGaN and Al a Ga 1-a N, or a combination of AlGaN, Al a Ga 1-a N, In c Al b Ga 1-b-c N and AlInGaN.

[0026] wherein 0

[0027] 0

[0028] 0

[0029] 0 < c < 1, for example can be 0.01, 0.03, 0.05, 0.1, 0.3, 0.5, 0.7 or 0.9, for example can be, but not limited to, the listed values, other values not listed in the value range are also applicable, the value range can be from large to small or from small to large, preferably from small to large.

[0030] Preferably, the stress adjustment layer further comprises a doping material, the doping material comprising any one or a combination of at least two of carbon, beryllium, magnesium or iron, typical but non-limiting combinations include a combination of carbon and beryllium, a combination of beryllium and magnesium, a combination of magnesium and iron, a combination of carbon and magnesium, a combination of carbon and iron, a combination of beryllium and iron, a combination of carbon, beryllium and magnesium, a combination of beryllium, magnesium and iron, or a combination of carbon, beryllium, magnesium and iron.

[0031] Preferably, the drift layer comprises GaN.

[0032] Preferably, the drift layer further comprises a doping material, the doping material comprising any one or a combination of at least two of carbon, beryllium, magnesium or iron, typical but non-limiting combinations include a combination of carbon and beryllium, a combination of beryllium and magnesium, a combination of magnesium and iron, a combination of carbon and magnesium, a combination of carbon and iron, a combination of beryllium and iron, a combination of carbon, beryllium and magnesium, a combination of beryllium, magnesium and iron, or a combination of carbon, beryllium, magnesium and iron.

[0033] Preferably, the cap layer comprises GaN.

[0034] Preferably, the thickness of the substrate is 300-1200 μm, for example can be 300 μm, 500 μm, 700 μm, 900 μm or 1200 μm, but not limited to the listed values, other values not listed in the value range are also applicable.

[0035] Preferably, the thickness of the buffer layer is 1-500 nm, for example can be 1 nm, 50 nm, 100 nm, 300 nm or 500 nm, but not limited to the listed values, other values not listed in the value range are also applicable.

[0036] Preferably, the thickness of the stress adjustment layer is 0.1-25 μm, for example can be 0.1 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm or 25 μm, but not limited to the listed values, other values not listed in the value range are also applicable, preferably 0.1-10 μm.

[0037] Preferably, the thickness of the drift layer is 0.1-50 μm, for example, it can be 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 30 μm or 50 μm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0038] Preferably, the thickness of the barrier layer is 0.1-200 nm, for example, it can be 0.1 nm, 0.5 nm, 1 nm, 5 nm, 10 nm, 50 nm, 100 nm, 150 nm or 200 nm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0039] Preferably, the thickness of the cap layer is 0.1-50 nm, for example, it can be 0.1 nm, 0.5 nm, 1 nm, 5 nm, 10 nm, 20 nm or 50 nm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0040] In a second aspect, the present application provides a method for preparing the gallium nitride-based epitaxial wafer according to the first aspect, characterized in that the method comprises the following steps:

[0041] (1) growing a buffer layer on the surface of the substrate;

[0042] (2) growing a stress adjustment layer on the surface of the obtained buffer layer;

[0043] (3) growing a drift layer on the surface of the obtained stress adjustment layer;

[0044] (4) growing a barrier layer on the surface of the obtained drift layer;

[0045] (5) growing a cap layer on the surface of the obtained barrier layer.

[0046] Preferably, the temperature for the growth in step (1) is 500-1100 °C, for example, it can be 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C or 1100 °C, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0047] Preferably, the pressure of the reaction chamber for the growth in step (1) is 20-500 torr, for example, it can be 20 torr, 50 torr, 100 torr, 200 torr or 500 torr, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0048] Preferably, the temperature for the growth in step (2) is 500-1100 °C, for example it can be 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C or 1100 °C, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0049] Preferably, the pressure of the reaction chamber for the growth in step (2) is 20-500 torr, for example it can be 20 torr, 50 torr, 100 torr, 200 torr or 500 torr, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0050] Preferably, the flow rate of TMAl for the growth in step (2) is 10-250 sccm, for example it can be 10 sccm, 50 sccm, 100 sccm, 150 sccm, 200 sccm or 250 sccm, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0051] Preferably, the flow rate of TMIn for the growth in step (2) is 10-200 sccm, for example it can be 10 sccm, 50 sccm, 100 sccm, 150 sccm or 200 sccm, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0052] Preferably, the flow rate of TMGa for the growth in step (2) is 10-50 sccm, for example it can be 5 sccm, 10 sccm, 20 sccm, 30 sccm, 40 sccm or 50 sccm, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0053] Preferably, the growth in step (2) is carried out under the condition of supplying ammonia and / or hydrogen.

[0054] Preferably, the flow rate of the hydrogen is 0.5-100 slm, for example it can be 0.5 slm, 1 slm, 10 slm, 20 slm, 40 slm, 50 slm, 70 slm or 100 slm, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0055] Preferably, the growth in step (2) is carried out under the condition of supplying ammonia, and the flow rate is 0.5-50 slm, for example it can be 0.5 slm, 1 slm, 5 slm, 10 slm, 25 slm or 50 slm, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0056] Preferably, the temperature of the growth in step (3) is 500-1100 °C, for example it can be 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C or 1100 °C, but is not limited to the listed values, other values not listed within the range of values are equally applicable.

[0057] Preferably, the pressure of the reaction chamber of the growth in step (3) is 20-500 torr, for example it can be 20 torr, 50 torr, 100 torr, 200 torr or 500 torr, but is not limited to the listed values, other values not listed within the range of values are equally applicable.

[0058] Preferably, the flow rate of TMGa of the growth in step (3) is 10-50 sccm, for example it can be 5 sccm, 10 sccm, 20 sccm, 30 sccm, 40 sccm or 50 sccm, but is not limited to the listed values, other values not listed within the range of values are equally applicable.

[0059] Preferably, the growth in step (3) is performed under the condition of supplying ammonia and / or hydrogen.

[0060] Preferably, the flow rate of the hydrogen is 0.5-1 slm, for example it can be 0.5 slm, 0.6 slm, 0.7 slm, 0.8 slm, 0.9 slm or 1 slm, but is not limited to the listed values, other values not listed within the range of values are equally applicable.

[0061] Preferably, the growth in step (3) is performed under the condition of supplying ammonia, and the flow rate is 0.5-100 slm, for example it can be 0.5 slm, 1 slm, 5 slm, 10 slm, 25 slm, 50 slm, 75 slm or 100 slm, but is not limited to the listed values, other values not listed within the range of values are equally applicable.

[0062] Preferably, the temperature of the growth in step (4) is 500-1100 °C, for example it can be 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C or 1100 °C, but is not limited to the listed values, other values not listed within the range of values are equally applicable.

[0063] Preferably, the pressure of the reaction chamber of the growth in step (4) is 20-500 torr, for example it can be 20 torr, 50 torr, 100 torr, 200 torr or 500 torr, but is not limited to the listed values, other values not listed within the range of values are equally applicable.

[0064] Preferably, the TMIn flow rate for the growth in step (4) is 10-200 sccm, for example, it can be 10 sccm, 50 sccm, 100 sccm, 150 sccm or 200 sccm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0065] Preferably, the TMGa flow rate for the growth in step (4) is 10-100 sccm, for example, it can be 10 sccm, 25 sccm, 50 sccm, 75 sccm or 100 sccm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0066] Preferably, the TMAl flow rate for the growth in step (4) is 10-300 sccm, for example, it can be 10 sccm, 50 sccm, 100 sccm, 150 sccm, 200 sccm, 250 sccm or 300 sccm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0067] Preferably, the growth in step (4) is carried out under the condition of supplying ammonia and / or hydrogen.

[0068] Preferably, the flow rate of the hydrogen is 0.5-100 slm, for example, it can be 0.5 slm, 10 slm, 20 slm, 30 slm, 40 slm, 60 slm, 80 slm or 100 slm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0069] Preferably, the growth in step (4) is carried out under the condition of supplying ammonia, and the flow rate is 0.5-100 slm, for example, it can be 0.5 slm, 1 slm, 5 slm, 10 slm, 25 slm, 50 slm, 60 slm, 80 slm or 100 slm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0070] Preferably, the temperature for the growth in step (5) is 500-1000°C, for example, it can be 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C or 1000°C, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0071] Preferably, the pressure of the reaction chamber for the growth in step (5) is 20-500 torr, for example, it can be 20 torr, 50 torr, 100 torr, 200 torr or 500 torr, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0072] Preferably, the TMGa flow rate for the growth in step (5) is 10-50 sccm, for example, it can be 10 sccm, 25 sccm or 50 sccm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0073] Preferably, the growth in step (5) is carried out under the condition of passing in ammonia and / or hydrogen.

[0074] Preferably, the flow rate of the hydrogen is 0.5-100 slm, for example, it can be 0.5 slm, 10 slm, 20 slm, 30 slm, 40 slm, 60 slm, 80 slm or 100 slm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0075] Preferably, the growth in step (5) is carried out under the condition of passing in ammonia, and the flow rate is 0.5-100 slm, for example, it can be 0.5 slm, 1 slm, 5 slm, 10 slm, 25 slm, 50 slm, 60 slm, 80 slm or 100 slm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0076] In a third aspect, the present application provides a power device containing the semiconductor epitaxial structure as described in the first aspect.

[0077] In a fourth aspect, the present application provides a radio frequency device containing the semiconductor epitaxial structure as described in the first aspect.

[0078] From the above technical solutions, the beneficial effects of the present application are as follows:

[0079] The gallium nitride-based epitaxial wafer provided by the present application grows a barrier layer, uses AlInN to make the band gap in the heterostructure larger, can eliminate dislocations caused by different lattice constants between the stress adjustment layer, and reduce the two-dimensional electron gas caused by the piezoelectric polarization electric field, and at the same time, the short channel effect caused by the continuously reduced gate in the HEMT device is improved, thereby improving the high-frequency switching speed of the device and improving the electrical characteristics of the device. BRIEF DESCRIPTION OF DRAWINGS

[0080] Figure 1 The gallium nitride-based epitaxial wafer provided by the present application grows a barrier layer, uses AlInN to make the band gap in the heterostructure larger, can eliminate dislocations caused by different lattice constants between the stress adjustment layer, and reduce the two-dimensional electron gas caused by the piezoelectric polarization electric field, and at the same time, the short channel effect caused by the continuously reduced gate in the HEMT device is improved, thereby improving the high-frequency switching speed of the device and improving the electrical characteristics of the device.

[0081] Among them, 1-substrate, 2-buffer layer, 3-stress adjustment layer, 4-drift layer, 5-barrier layer, 6-cap layer. DETAILED DESCRIPTION

[0082] The technical solutions of the present application are further illustrated below in combination with the drawings and through specific embodiments. However, the following examples are merely simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0083] Embodiment 1

[0084] The present embodiment provides a gallium nitride-based epitaxial wafer (1) comprising a substrate 1, a buffer layer 2, a stress adjustment layer 3, a drift layer 4, a barrier layer 5 and a cap layer 6 which are stacked. Figure 1

[0085] The substrate 1 is made of Al2O3 and has a thickness of 460 μm.

[0086] The buffer layer 2 is made of AlN and doped with beryllium at a doping concentration of 1.0 x E18 atoms / cm2and has a thickness of 250 nm. 3

[0087] The stress adjustment layer 3 is made of AlInGaN and doped with iron at a doping concentration of 1.0 x E18 atoms / cm2and has a thickness of 250 nm. 3

[0088] The drift layer 4 comprises a semiconductor material GaN and is doped with carbon at a doping concentration of 1.0 x E18 atoms / cm2and has a thickness of 10 μm. 3

[0089] The barrier layer 5 is a single layer of AlInN and is doped with silicon at a doping concentration of 1.0 x E18 atoms / cm2and has a thickness of 25 nm. 3

[0090] The cap layer 6 is a single layer of GaN and has a thickness of 25 nm.

[0091] The method for preparing the gallium nitride-based epitaxial wafer comprises the following steps:

[0092] (1) under the conditions of a temperature of 800°C, a reaction cavity pressure of 260 torr and a TMAl flow rate of 100 sccm, ammonia gas is introduced at a flow rate of 25 slm and hydrogen gas is introduced at a flow rate of 50 slm to grow the buffer layer 2 on the surface of the substrate 1;

[0093] (2) under the conditions of a temperature of 800°C, a reaction cavity pressure of 260 torr, a TMAl flow rate of 130 sccm, a TMGa flow rate of 25 sccm and a TMIn flow rate of 100 sccm, ammonia gas is introduced at a flow rate of 25 slm to grow the stress adjustment layer 3 on the surface of the obtained buffer layer 2; ​​​​​

[0094] (3) Under the conditions of 800℃, 260 torr in reaction chamber, and 25 sccm in TMGa flow rate, ammonia gas with a flow rate of 50 slm and hydrogen gas with a flow rate of 0.5 slm are introduced to grow a drift layer 4 on the surface of the obtained stress-adjusting layer 3.

[0095] (4) Under the conditions of 800℃, 260 torr, 150 sccm flow rate of TMAl, and 50 sccm flow rate of TMIn, ammonia gas with a flow rate of 50 slm is introduced to grow a barrier layer 5 on the surface of the obtained drift layer 4.

[0096] (5) Under the conditions of 800℃, 200 torr pressure in the reaction chamber and 25 sccm flow rate of TMGa, ammonia gas with a flow rate of 50 slm is introduced to grow a capping layer 6 on the surface of the obtained barrier layer 5.

[0097] Example 2

[0098] This embodiment provides a gallium nitride-based epitaxial wafer ( Figure 1 The gallium nitride-based epitaxial wafer includes a substrate 1, a buffer layer 2, a stress adjustment layer 3, a drift layer 4, a barrier layer 5, and a capping layer 6 stacked together.

[0099] The substrate 1 is made of GaN and has a thickness of 500 μm.

[0100] The buffer layer 2 is AlN, with magnesium as the doping material and a doping concentration of 1.0 × E17 atoms / cm. 3 The thickness is 1 nm.

[0101] The stress-adjusting layer 3 is made of Al 0.5 Ga 0.5 N and In 0.3 Al 0.2 Ga 0.5 The composite layer is composed of N atoms arranged in a periodic pattern with a period number of 3. The stress-regulating layer 3 is doped with iron at a concentration of 1.0 × E17 atoms / cm². 3 The thickness is 10nm.

[0102] The drift layer 4 includes the semiconductor material GaN and has a thickness of 0.05 μm.

[0103] The barrier layer 5 consists of two layers, each containing AlInN and AlN semiconductor materials respectively.

[0104] The capping layer 6 is a single layer of GaN with a thickness of 0.1 nm.

[0105] The method for preparing the gallium nitride-based epitaxial wafer includes the following steps:

[0106] (1) Under the conditions of a temperature of 500°C, a reaction cavity pressure of 20 torr, a TMAl flow rate of 10 sccm, a flow rate of 0.5 slm of ammonia gas, and a flow rate of 0.5 slm of hydrogen gas, a buffer layer 2 is grown on the surface of the substrate 1;

[0107] (2) Under the conditions of a temperature of 500°C, a reaction cavity pressure of 20 torr, a TMAl flow rate of 10 sccm, a TMGa flow rate of 10 sccm, a flow rate of 0.5 slm of ammonia gas, and a flow rate of 0.5 of hydrogen gas, Al in a stress adjustment layer 3 is grown on the surface of the buffer layer 2 0.5 Ga 0.5 N, under the conditions of a temperature of 500°C, a reaction cavity pressure of 20 torr, a TMAl flow rate of 30 sccm, a TMIn flow rate of 20 sccm, a TMGa flow rate of 50 sccm, a flow rate of 0.5 slm of ammonia gas, and a flow rate of 0.5 slm of hydrogen gas, In in the stress adjustment layer 3 is grown on the surface of the buffer layer 2 0.3 Al 0.2 Ga 0.5 N;

[0108] (3) Under the conditions of a temperature of 500°C, a reaction cavity pressure of 20 torr, a TMGa flow rate of 10 sccm, a flow rate of 0.5 slm of ammonia gas, a drift layer 4 is grown on the surface of the stress adjustment layer 3;

[0109] (4) Under the conditions of a temperature of 500°C, a reaction cavity pressure of 20 torr, a TMAl flow rate of 10 sccm, a TMIn flow rate of 10 sccm, a flow rate of 0.5 slm of ammonia gas, an AlInN layer in a barrier layer 5 is grown on the surface of the drift layer 4, under the conditions of a temperature of 500°C, a reaction cavity pressure of 20 torr, a TMAl flow rate of 10 sccm, a flow rate of 0.5 slm of ammonia gas, and a flow rate of 0.5 slm of hydrogen gas, an AlN layer in the barrier layer 5 is grown on the surface of the drift layer 4;

[0110] (5) Under the conditions of a temperature of 1000°C, a reaction cavity pressure of 300 torr, a flow rate of 25 slm of ammonia gas, and a TMGa flow rate of 25 sccm, a cap layer 6 is grown on the surface of the barrier layer 5.

[0111] Example 3

[0112] The present embodiment provides a gallium nitride-based epitaxial wafer Figure 1 ), which includes a substrate 1, a buffer layer 2, a stress adjustment layer 3, a drift layer 4, a barrier layer 5, and a cap layer 6 which are stacked.

[0113] The substrate 1 is made of Si and has a thickness of 1200 μm.

[0114] The buffer layer 2 is made of single layer AlN and doped with magnesium at a doping concentration of 1.0 x E19 atoms / cm 3 , and has a thickness of 500 nm.

[0115] The stress adjusting layer 3 is made of double layer of GaN or In 0.3 Al 0.2 Ga 0.5 N and doped with iron at a doping concentration of 1.0 x E19 atoms / cm 3 , and has a thickness of 500 nm.

[0116] The drift layer 4 is made of single layer GaN and doped with carbon at a doping concentration of 1.0 x E19 atoms / cm 3 , and has a thickness of 20 μm.

[0117] The barrier layer 5 is made of composite layer of AlN and InAlGaN and arranged in a periodic pattern with a period of 3, and each layer is doped with silicon at a doping concentration of 1.0 x E19 atoms / cm 3 , and has a thickness of 50 nm.

[0118] The cap layer 6 is made of single layer GaN and has a thickness of 50 nm.

[0119] The method for preparing the GaN-based epitaxial wafer comprises the following steps:

[0120] (1) under the conditions of a temperature of 1100 °C, a reaction cavity pressure of 500 torr, and a TMAl flow rate of 250 sccm, ammonia gas with a flow rate of 50 slm and hydrogen gas with a flow rate of 50 slm are introduced to grow the buffer layer 2 on the surface of the substrate 1;

[0121] (2) under the conditions of a temperature of 1100 °C, a reaction cavity pressure of 500 torr, and a TMGa flow rate of 50 sccm, ammonia gas with a flow rate of 50 slm is introduced to grow GaN in the stress adjusting layer 3 on the surface of the obtained buffer layer 2, and under the conditions of a temperature of 1100 °C, a reaction cavity pressure of 500 torr, a TMGa flow rate of 50 sccm, a TMIn flow rate of 30 sccm, and a TMAl flow rate of 20 sccm, ammonia gas with a flow rate of 50 slm is introduced to grow In 0.3 Al 0.2 Ga 0.5 N in the stress adjusting layer 3 on the surface of the obtained buffer layer 2;

[0122] (3) Under the conditions of a temperature of 1100°C, a reaction cavity pressure of 500 torr, a TMGa flow rate of 300 sccm, and an ammonia gas flow rate of 50 slm, a drift layer 4 is grown on the surface of the stress adjustment layer 3 obtained;

[0123] (4) Under the conditions of a temperature of 1100°C, a reaction cavity pressure of 500 torr, a TMAl flow rate of 200 sccm, a TMIn flow rate of 200 sccm, a TMGa flow rate of 200 sccm, and an ammonia gas flow rate of 100 slm, an InAlGaN layer in the barrier layer 5 is grown on the surface of the drift layer 4 obtained, and under the conditions of a temperature of 1100°C, a reaction cavity pressure of 500 torr, a TMAl flow rate of 300 sccm, and a hydrogen gas flow rate of 100 slm, an AlN layer in the barrier layer 5 is grown on the surface of the drift layer 4 obtained;

[0124] (5) Under the conditions of a temperature of 900°C, a reaction cavity pressure of 250 torr, an ammonia gas flow rate of 35 slm, and a TMGa flow rate of 25 sccm, a cap layer 6 is grown on the surface of the barrier layer 5 obtained.

[0125] Example 4

[0126] This example provides a gallium nitride-based epitaxial wafer, which is identical to Example 1 except that the thickness of the barrier layer is 0.05 nm.

[0127] Example 5

[0128] This example provides a gallium nitride-based epitaxial wafer, which is identical to Example 1 except that the thickness of the barrier layer is 250 nm.

[0129] Comparative Example 1

[0130] This comparative example provides a gallium nitride-based epitaxial wafer, which is identical to Example 1 except that the AlInN in the barrier layer is replaced with an equal amount of InN.

[0131] Comparative Example 2

[0132] This comparative example provides a gallium nitride-based epitaxial wafer, which is identical to Example 1 except that the AlInN in the barrier layer is replaced with an equal amount of GaN.

[0133] From the above-described nitride epitaxial layer, the following conclusions can be drawn:

[0134] (1) From Examples 1-3, it can be seen that the gallium nitride-based epitaxial wafer provided by the application grows a barrier layer, which makes the band gap in the heterostructure have a larger band offset, eliminates dislocations caused by different lattice constants between the channel layer and the stress adjustment layer, and reduces the surface density in the two-dimensional electron gas caused by the piezoelectric polarization electric field, while improving the short channel effect caused by the continuously reduced gate in the HEMT device, thereby improving the high-frequency switching speed of the device and improving the electrical properties of the device.

[0135] (2) From the comparison of Examples 4, 5 and 1, it can be seen that when the thickness of the barrier layer is not within the range of 0.1-200 nm provided by the application, the obtained gallium nitride-based epitaxial wafer has poor crystal quality, reduced surface density, and reduced device electrical performance.

[0136] (5) From the comparison of Comparative Examples 1, 2 and Example 1, it can be seen that when the material in the barrier layer is not within the range provided by the application, the barrier layer does not contain Al or only contains In, the obtained gallium nitride-based epitaxial wafer has poor crystal quality, reduced surface density, and reduced device electrical performance.

[0137] In summary, the gallium nitride-based epitaxial wafer provided by the application grows a barrier layer, which makes the band gap in the heterostructure have a larger band offset, eliminates dislocations caused by different lattice constants between the channel layer and the stress adjustment layer, and reduces the surface density in the two-dimensional electron gas caused by the piezoelectric polarization electric field, while improving the short channel effect caused by the continuously reduced gate in the HEMT device, thereby improving the high-frequency switching speed of the device and improving the electrical properties of the device.

[0138] The above examples are used to illustrate the detailed structural features of the application, but the application is not limited to the above detailed structural features, i.e. it does not mean that the application must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement on the application, equivalent replacement of the components selected by the application, addition of auxiliary components, selection of specific modes, etc. all fall within the protection scope and disclosure scope of the application.

Claims

1. A gallium nitride based epitaxial wafer, characterized by, The gallium nitride-based epitaxial wafer comprises a substrate, a buffer layer, a stress-regulating layer, a drift layer, a barrier layer, and a capping layer stacked together; the semiconductor material in the stress-regulating layer includes AlN, GaN, AlGaN, and Al a Ga 1-a N、In c Al b Ga 1-b-c The stress-adjusting layer further includes any one or a combination of at least two of N or AlInGaN, wherein 0 < a < 1, 0 < b < 1, 0 < c < 1; the stress-adjusting layer further includes a doped material, wherein the doped material includes any one or a combination of at least two of carbon, beryllium, magnesium or iron; the thickness of the stress-adjusting layer is 0.1 to 25 μm; The buffer layer comprises AlN and a doping material, the doping material comprising any one or a combination of at least two of carbon, beryllium, magnesium or iron; The drift layer comprises GaN, and further comprises a doping material, the doping material comprising any one or a combination of at least two of carbon, beryllium, magnesium or iron; The barrier layer is a single layer, and the semiconductor material includes any one or a combination of at least two of AlInN, AlN or InAlGaN; or the barrier layer is a composite layer structure, and the semiconductor material includes any one or a combination of at least two of AlN, Al x In y N or In y Al 1-x Ga 1-x-y N, wherein 0.1≤x≤1 and 0≤y≤1, and the thickness of the barrier layer is in the range of 0.1-200 nm. The barrier layer is used to eliminate dislocations between the drift layer and the stress adjustment layer due to different lattice constants, and to reduce the surface density in the two-dimensional electron gas caused by the piezoelectric polarization electric field; The substrate comprises any one of Al2O3, GaN, AlN, GaO, Si or SiC.

2. The gallium nitride-based epiwafer of claim 1 wherein, The stress adjustment layer comprises a single layer and / or a composite layer structure.

3. The gallium nitride-based epiwafer of claim 1 wherein, The cap layer comprises GaN.

4. The gallium nitride-based epiwafer of claim 1 wherein, The thickness of the substrate is 300-1200 μm.

5. The gallium nitride based epitaxial wafer of claim 1 wherein, The thickness of the buffer layer is 1-500 nm.

6. The gallium nitride based epitaxial wafer of claim 1 wherein, The thickness of the drift layer is 0.1-50 μm.

7. The gallium nitride based epitaxial wafer of claim 1 wherein, The thickness of the cap layer is 0.1-50 nm.

8. A method of producing a gallium nitride-based epitaxial wafer according to any one of claims 1 to 7, characterized by, The preparation method comprises the following steps: (1) growing a buffer layer on the surface of a substrate; (2) growing a stress adjustment layer on the surface of the obtained buffer layer; (3) growing a drift layer on the surface of the obtained stress adjustment layer; (4) growing a barrier layer on the surface of the obtained drift layer; (5) growing a cap layer on the surface of the obtained barrier layer.

9. The method of producing a gallium nitride based epitaxial wafer according to claim 8, wherein The temperature of the growth in step (1) is 500-1100 °C.

10. The method of producing a gallium nitride based epitaxial wafer according to claim 8, wherein The reaction cavity pressure of the growth in step (1) is 20-500 torr.

11. The method of producing a gallium nitride based epitaxial wafer according to claim 8, wherein The temperature of the growth in step (2) is 500-1100 °C.

12. The method of producing a gallium nitride based epitaxial wafer according to claim 8, wherein The reaction cavity pressure of the growth in step (2) is 20-500 torr.

13. The method of producing a gallium nitride based epitaxial wafer according to claim 8, wherein The TMAl flow rate of the growth in step (2) is 10-250 sccm.

14. The method of producing a gallium nitride based epitaxial wafer according to Claim 8, wherein The TMIn flow rate of the growth in step (2) is 10-200 sccm.

15. The method of producing a gallium nitride based epitaxial wafer according to Claim 8, wherein The TMGa flow rate of the growth in step (2) is 10-50 sccm.

16. The method of producing a gallium nitride based epitaxial wafer according to Claim 8, wherein The growth in step (2) is carried out under the condition of supplying ammonia and / or hydrogen.

17. The method of producing a gallium nitride based epitaxial wafer according to claim 16, wherein The flow rate of the ammonia is 0.5-50 slm.

18. The method of producing a gallium nitride based epitaxial wafer according to claim 16, wherein The flow rate of the hydrogen is 0.5-100 slm.

19. The method of producing a gallium nitride based epitaxial wafer according to Claim 8, wherein The temperature of the growth in step (3) is 500-1100 °C.

20. The method of producing a gallium nitride based epitaxial wafer according to Claim 8, wherein The reaction cavity pressure of the growth in step (3) is 20-500 torr.

21. The method of producing a gallium nitride based epitaxial wafer according to claim 8, wherein The TMGa flow rate of the growth in step (3) is 10-50 sccm.

22. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The growth in step (3) is carried out under the condition of supplying ammonia and / or hydrogen.

23. The method of producing a gallium nitride based epitaxial wafer according to claim 22, wherein The flow rate of the ammonia is 0.5-100 slm.

24. The method of producing a gallium nitride based epitaxial wafer according to Claim 22, wherein The flow rate of the hydrogen is 0.5-1 slm.

25. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The temperature of the growth in step (4) is 500-1100 °C.

26. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The reaction cavity pressure of the growth in step (4) is 20-500 torr.

27. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The TMAl flow rate of the growth in step (4) is 10-300 sccm.

28. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The TMGa flow rate of the growth in step (4) is 10-100 sccm.

29. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The TMIn flow rate of the growth in step (4) is 10-200 sccm.

30. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The growth in step (4) is carried out under the condition of supplying ammonia and / or hydrogen.

31. The method of producing a gallium nitride based epiwafer as recited in claim 30, wherein The flow rate of the ammonia is 0.5-100 slm.

32. The method of producing a gallium nitride based epiwafer as recited in claim 30, wherein The flow rate of the hydrogen is 0.5-100 slm.

33. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The temperature for the growth in step (5) is 500-1000 °C.

34. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The pressure of the reaction chamber for the growth in step (5) is 20-500 torr.

35. The method of producing a gallium nitride based epiwafer as defined in claim 8, wherein The TMGa flow rate for the growth in step (5) is 10-50 seem.

36. The method of producing a gallium nitride based epiwafer as recited in claim 8, wherein The growth in step (5) is performed under the condition that ammonia and / or hydrogen is introduced.

37. The method of producing a gallium nitride based epiwafer as recited in claim 36, wherein The flow rate of the ammonia is 0.5-100 slm.

38. The method of producing a gallium nitride based epiwafer as recited in claim 36, wherein The flow rate of the hydrogen is 0.5-100 slm.

39. A power device, characterized by The power device contains a gallium nitride based epitaxial wafer as claimed in any one of claims 1-7.

40. A radio-frequency device, characterized by The radio frequency device contains a gallium nitride based epitaxial wafer as claimed in any one of claims 1-7.

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