CN110828291A - GaN/AlGaN heterojunction material based on single crystal diamond substrate and preparation method thereof - Google Patents

Abstract

The invention relates to a GaN/AlGaN heterojunction material based on a single crystal diamond substrate and a preparation method thereof. The method comprises: selecting a single crystal diamond substrate; generating graphene on the upper surface of the single crystal diamond substrate growing an AlN nucleation layer on the upper surface of the graphene layer; growing a low temperature GaN transition layer on the upper surface of the AlN nucleation layer; growing a GaN buffer layer on the upper surface of the low temperature GaN transition layer; An AlGaN barrier layer is grown on the upper surface of the GaN buffer layer. The GaN/AlGaN heterojunction material and preparation method can grow the GaN/AlGaN heterojunction material on the single crystal diamond substrate of any crystal plane by transferring graphene to the single crystal diamond substrate of any crystal plane, breaking through the The limitation on the crystal plane of the substrate when epitaxial GaN material on diamond is simplified, the process difficulty is simplified and the quality of the heterojunction material is improved.

Description

GaN/AlGaN heterojunction material based on single crystal diamond substrate and preparation method thereof

technical field

The invention belongs to the technical field of microelectronics, and in particular relates to a GaN/AlGaN heterojunction material based on a single crystal diamond substrate and a preparation method thereof.

Background technique

Nitride semiconductor materials have the advantages of large band gap, high carrier mobility, and strong breakdown field, and have great application potential in high-frequency, high-voltage, and high-power semiconductor devices. Generally, nitride semiconductor materials are epitaxially grown on Si, sapphire or SiC substrates, but these substrates have relatively low thermal conductivity, resulting in poor heat dissipation performance of nitride-based semiconductor devices, which severely limits nitrides. Applications of semiconductor devices under high power conditions.

Diamond has the highest thermal conductivity in nature and is especially suitable for heat dissipation applications such as heat sinks. If the epitaxial growth of the nitride material on the diamond substrate can be realized, the heat dissipation problem in the high-power application of the nitride material can be solved, and the development of the nitride material and the device can be promoted. Kazuyuki Hirama et al. in their paper "Epitaxial Growth of AlGaN/GaN High-Electron Mobility Transistor Structure on Diamond (111) Surface" (Japanese Journal of Applied Physics 51 (2012) 090114) discloses a method for growing AlGaN/GaN heterojunction materials directly on a (111) plane diamond substrate, and fabricates transistor devices accordingly.

However, in the above paper, the AlN nucleation layer grown by MOCVD (Metal Organic Chemical Vapor Deposition) is directly used for epitaxial growth of GaN material on the (111) plane diamond substrate. On the one hand, the lattice mismatch between GaN and diamond is large, resulting in The poor quality of the material and the difficulty in growth limit the characteristics of the resulting device; on the other hand, the (111) plane diamond substrate is difficult to grow and its size is small, which makes the overall manufacturing cost of the device high.

SUMMARY OF THE INVENTION

In order to solve the above problems existing in the prior art, the present invention provides a GaN/AlGaN heterojunction material based on a single crystal diamond substrate and a preparation method thereof. The technical problem to be solved by the present invention is realized by the following technical solutions:

One aspect of the present invention provides a preparation method of a GaN/AlGaN heterojunction material based on a single crystal diamond substrate, comprising:

S1: Select a single crystal diamond substrate;

S2: generating a graphene layer on the upper surface of the single crystal diamond substrate;

S3: growing an AlN nucleation layer on the upper surface of the graphene layer;

S4: growing a low temperature GaN transition layer on the upper surface of the AlN nucleation layer;

S5: growing a GaN buffer layer on the upper surface of the low-temperature GaN transition layer;

S6: growing an AlGaN barrier layer on the upper surface of the GaN buffer layer, thereby forming a GaN/AlGaN heterojunction material based on a single crystal diamond substrate.

In an embodiment of the present invention, the S1 includes:

A single crystal diamond with a thickness of 0.3-1 mm and a crystal plane of (100) or (110) or (111) is selected as the substrate.

In an embodiment of the present invention, the S2 includes:

S21: growing a graphene layer with a thickness of 0.2-0.4 nm on a metal substrate;

S22: chemically corrode the metal substrate covered with the graphene layer to remove the metal substrate;

S23: Transfer the graphene layer to the single crystal diamond substrate to obtain a single crystal diamond substrate covered with a graphene layer.

In an embodiment of the present invention, the S3 includes:

S31: select Al with a mass percentage greater than 99.999% as the sputtering target;

S32: Select nitrogen with a mass percentage greater than 99.999% and argon with a mass percentage greater than 99.999% as the sputtering gas, and pass the two kinds of sputtering gases into the sputtering chamber at the same time;

S33: Sputtering is performed on the upper surface of the graphene layer by using a magnetron sputtering technology to generate an AlN nucleation layer.

In an embodiment of the present invention, the S4 includes:

S41: use trimethyl gallium as the Ga source and ammonia as the N source, and simultaneously pass into the gas-phase precipitation reaction chamber;

S42: Under the conditions that the pressure of the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature is 450-600° C., the flow rate of ammonia gas is 3000-5000 sccm, and the flow rate of trimethyl gallium is 100-200 sccm, using metal organic compound chemical vapor deposition The technique grows a low temperature GaN transition layer on the upper surface of the AlN nucleation layer.

In an embodiment of the present invention, the S5 includes:

S51: use trimethyl gallium as the Ga source and ammonia as the N source, and simultaneously pass into the gas-phase precipitation reaction chamber;

S52: Under the conditions that the pressure of the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature is 900-1000° C., the flow rate of ammonia gas is 3000-5000 sccm, and the flow rate of trimethyl gallium is 100-200 sccm, using metal organic compound chemical vapor deposition technology grows a GaN buffer layer on the upper surface of the low temperature GaN transition layer.

In an embodiment of the present invention, the S6 includes:

S61: use trimethyl gallium as the Ga source, trimethyl aluminum as the Al source, and ammonia as the N source, and simultaneously pass into the vapor deposition reaction chamber;

S62: The pressure in the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature range is 1000-1100 ℃, the flow rate of ammonia gas is 3000-5000 sccm, the flow rate of trimethyl gallium is 30-60 sccm, and the flow rate of trimethyl aluminum is 800-1000 sccm The AlGaN barrier layer is grown on the upper surface of the GaN buffer layer by using the metal organic compound chemical vapor deposition technology under the conditions of the present invention.

Another aspect of the present invention provides a GaN/AlGaN heterojunction material based on a single crystal diamond substrate, the material including, from bottom to top, a single crystal diamond substrate, a graphene layer, an AlN nucleation layer, and a low-temperature GaN layer. Transition layer, GaN buffer layer and AlGaN barrier layer.

In one embodiment of the present invention, the crystal plane of the single crystal diamond substrate is (100) or (110) or (111).

In an embodiment of the present invention, the thickness of the single crystal diamond substrate is 0.3-1 mm, the thickness of the graphene layer is 0.2-0.4 nm, and the thickness of the AlN nucleation layer is 20-100 nm, so The thickness of the low temperature GaN transition layer is 20-200 nm, the thickness of the GaN buffer layer is 0.1-5 μm, and the thickness of the AlGaN barrier layer is 5-100 nm.

Compared with the prior art, the beneficial effects of the present invention are:

1. The preparation method of the present invention reduces the stress between the substrate and the GaN layer by transferring a layer of graphene on the single crystal diamond substrate and growing the GaN layer on the graphene layer, thereby providing a The method of growing GaN/AlGaN heterojunction materials on a single crystal diamond substrate with a crystal plane breaks through the limitation of epitaxial gallium nitride materials on diamond on the crystal plane of the substrate, simplifies the process difficulty, and realizes large-area and high heat dissipation efficiency. Growth of gallium nitride heterojunction materials.

2. The present invention adopts the method of magnetron sputtering to grow an AlN nucleation layer on the graphene layer, which can grow a high-quality AlN nucleation layer on the graphene, and use MOCVD (metal organic compound chemical compound) on the AlN nucleation layer. The GaN/AlGaN heterojunction material is grown by vapor deposition) technology, so that the GaN material grown on the single crystal diamond substrate has the advantages of good heat dissipation, high quality, simple process and low cost.

Description of drawings

1 is a flowchart of a method for preparing a GaN/AlGaN heterojunction material based on a single crystal diamond substrate provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a GaN/AlGaN heterojunction material based on a single crystal diamond substrate provided by an embodiment of the present invention.

Detailed ways

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

Example 1

Please refer to FIG. 1. FIG. 1 is a flowchart of a method for preparing a GaN/AlGaN heterojunction material based on a single crystal diamond substrate provided by an embodiment of the present invention. The preparation method of this embodiment includes:

S1: Select a single crystal diamond substrate;

S2: generating a graphene layer on the upper surface of the single crystal diamond substrate;

S3: growing an AlN nucleation layer on the upper surface of the graphene layer;

S4: growing a low temperature GaN transition layer on the upper surface of the AlN nucleation layer;

S5: growing a GaN buffer layer on the upper surface of the low-temperature GaN transition layer;

S6: growing an AlGaN barrier layer on the upper surface of the GaN buffer layer, and finally forming a GaN/AlGaN heterojunction material based on a single crystal diamond substrate.

Further, the S1 includes:

A single crystal diamond with a thickness of 0.3-1 mm and a crystal plane of (100) or (110) or (111) is selected as the substrate.

Further, the S2 includes:

S21: growing a graphene layer with a thickness of 0.2-0.4 nm on a metal substrate;

S22: chemically corrode the metal substrate covered with the graphene layer to remove the metal substrate;

S23: Transfer the graphene layer to a single crystal diamond substrate to obtain a single crystal diamond substrate covered with a graphene layer.

Further, the S3 includes:

S31: select Al with a mass percentage greater than 99.999% as the sputtering target;

S32: Select nitrogen with a mass percentage greater than 99.999% and argon with a mass percentage greater than 99.999% as the sputtering gas, and pass the two kinds of sputtering gases into the sputtering chamber at the same time;

S33: Sputtering is performed on the upper surface of the graphene layer by using a magnetron sputtering technology to generate an AlN nucleation layer.

Further, the S4 includes:

S41: use trimethyl gallium as the Ga source and ammonia as the N source, and simultaneously pass into the gas-phase precipitation reaction chamber;

S42: under the conditions that the pressure of the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature range is 450-600 ℃, the flow rate of ammonia gas is 3000-5000 sccm, and the flow rate of trimethyl gallium is 100-200 sccm, the MOCVD technology is used in the described A low temperature GaN transition layer is grown on the upper surface of the AlN nucleation layer.

Further, the S5 includes:

S51: use trimethyl gallium as the Ga source and ammonia as the N source, and simultaneously pass into the gas-phase precipitation reaction chamber;

S52: under the conditions that the pressure of the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature range is 900-1000 ℃, the flow rate of ammonia gas is 3000-5000 sccm, and the flow rate of trimethyl gallium is 100-200 sccm, the MOCVD technology is used in the described A GaN buffer layer is grown on the upper surface of the low temperature GaN transition layer.

Further, the S6 includes:

S61: use trimethyl gallium as the Ga source, trimethyl aluminum as the Al source, and ammonia as the N source, and simultaneously pass into the vapor deposition reaction chamber;

S62: The pressure in the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature range is 1000-1100 ℃, the flow rate of ammonia gas is 3000-5000 sccm, the flow rate of trimethyl gallium is 30-60 sccm, and the flow rate of trimethyl aluminum is 800-1000 sccm Under the condition of , an AlGaN barrier layer is grown on the upper surface of the GaN buffer layer by using MOCVD technology.

The preparation method of the invention reduces the stress between the substrate and the GaN layer by transferring a layer of graphene on the single crystal diamond substrate, and provides a method for growing GaN/GaN on the single crystal diamond substrate of any crystal plane. The method of AlGaN heterojunction material breaks through the limitation of epitaxial gallium nitride material on diamond on the crystal plane of the substrate, simplifies the process difficulty, and realizes the growth of gallium nitride heterojunction material with large area and high heat dissipation efficiency.

Embodiment 2

On the basis of the above examples, a GaN/AlGaN heterostructure based on a (100) crystal plane single crystal diamond substrate and comprising a 20 nm AlN nucleation layer, a 20 nm low temperature GaN transition layer, a 0.1 μm GaN buffer layer and a 10 nm AlGaN barrier layer was prepared. Taking the mass junction material as an example, this embodiment will describe the preparation method of the embodiment of the present invention in detail.

The preparation method of this embodiment includes:

Step 1: Select a single crystal diamond substrate;

A single crystal diamond with a thickness of 0.5 mm and a crystal plane of (100) was selected as the substrate.

Step 2: generating a graphene layer on the upper surface of the (100) single crystal diamond substrate;

Specifically, a graphene layer of 0.2 mm is grown by chemical vapor deposition on the metal substrate; then the metal substrate covered with the graphene layer is placed in 1 mol/L ferric chloride and 2 mol/L hydrochloric acid in a volume ratio of 1 : 2 in the mixed solution for 18 hours to remove the metal substrate; finally, the graphene layer is transferred to the (100) single crystal diamond substrate to obtain a (100) single crystal diamond substrate covered with graphene.

Step 3: using a magnetron sputtering process to grow an AlN nucleation layer on the upper surface of the graphene layer;

Specifically, the (100) crystal plane single crystal diamond substrate covered with the graphene layer obtained in step 2 of this embodiment is placed in a magnetron sputtering system, and nitrogen gas with a mass percentage greater than 99.999% and a mass percentage greater than 99.999% are introduced % argon as the sputtering gas, and Al with a mass percentage greater than 99.999% as the sputtering target, sputter 20 nm AlN on the graphene to form an AlN nucleation layer. During the sputtering process, the substrate temperature is 650°C, the flow rate of argon gas is 5 sccm, and the flow rate of nitrogen gas is 10 sccm.

Step 4: growing a low temperature GaN transition layer on the upper surface of the AlN nucleation layer;

Specifically, the substrate on which the AlN nucleation layer has grown is placed in a MOCVD vapor deposition reaction chamber, the temperature of the vapor deposition reaction chamber is gradually adjusted to 450° C., and trimethyl gallium is brought in as a Ga source with hydrogen as the carrier gas. Ammonia gas was introduced as an N source, and the pressure in the vapor deposition reaction chamber was kept at 40 Torr; a low-temperature GaN transition layer was grown on the upper surface of the AlN nucleation layer by using MOCVD technology, wherein, during the growth process, the hydrogen flow rate was 800sccm, and the ammonia flow rate was 800sccm. The gas flow rate was 3000 sccm, the trimethyl gallium flow rate was 100 sccm, the growth time was 10 minutes, and the thickness of the grown low-temperature GaN transition layer was 20 nm.

Step 5: growing a GaN buffer layer on the upper surface of the low temperature GaN transition layer;

Specifically, the temperature in the MOCVD vapor deposition reaction chamber was adjusted to 900°C, trimethyl gallium was introduced into the MOCVD vapor deposition reaction chamber as the Ga source, and ammonia was introduced as the N source at the same time, and the pressure in the vapor deposition reaction chamber was kept as 40 Torr; using MOCVD technology to grow a GaN buffer layer on the upper surface of the low-temperature GaN transition layer, wherein, during the growth process, the flow rate of hydrogen gas is 800sccm, the flow rate of ammonia gas is 3000sccm, the flow rate of trimethyl gallium is 100sccm, and the growth time is 10 minutes. The thickness of the grown GaN buffer layer was 100 nm.

Step 6: growing an AlGaN barrier layer on the upper surface of the GaN buffer layer;

Specifically, the temperature in the MOCVD vapor deposition reaction chamber was gradually increased to 1000 °C, and trimethylgallium and trimethylaluminum were brought in with hydrogen as the carrier gas as the Ga source and the Al source, respectively, and ammonia gas was introduced as the N source, and keep the pressure in the vapor deposition reaction chamber at 40 Torr, and use MOCVD technology to grow the AlGaN barrier layer on the upper surface of the GaN buffer layer. During the growth process, the flow rate of hydrogen gas is 800sccm, the flow rate of ammonia The flow rate was 30 sccm, the flow rate of trimethyl aluminum was 800 sccm, the growth time was 1 minute, and the thickness of the grown AlGaN barrier layer was 5 nm.

Step 7: Take the slice.

The GaN/AlGaN heterojunction material of the finally formed (100) crystal plane single crystal diamond substrate was taken out from the MOCVD vapor deposition reaction chamber.

Embodiment 3

In this example, a GaN/AlGaN heterogeneity including a 100 nm AlN nucleation layer, a 200 nm low temperature GaN transition layer, a 0.5 μm GaN buffer layer and a 100 nm AlGaN barrier layer was prepared by preparing a (110) crystal plane-based single crystal diamond substrate. Taking the junction material as an example, the preparation method of the embodiment of the present invention will be described in detail.

The preparation method of this embodiment includes:

Step 1: Select a single crystal diamond substrate;

A single crystal diamond with a thickness of 0.5 mm and a crystal plane of (110) was selected as the substrate.

Step 2: generating a graphene layer on the upper surface of the (110) single crystal diamond substrate;

Specifically, adopt chemical vapor deposition method to grow 0.3mm graphene layer on metal substrate; Then the metal substrate that is covered with graphene layer is placed in 1mol/L ferric chloride and 2mol/L hydrochloric acid by volume 1: 1. In the mixed solution for 10 hours, the metal substrate is removed; finally, the graphene layer is transferred to the (110) single crystal diamond substrate to obtain the (110) single crystal diamond substrate covered with graphene.

Step 3: using a magnetron sputtering process to grow an AlN nucleation layer on the upper surface of the graphene layer;

Specifically, the (110) crystal plane single crystal diamond substrate covered with the graphene layer obtained in step 2 of this embodiment is placed in a magnetron sputtering system, and nitrogen gas with a mass percentage greater than 99.999% and a mass percentage greater than 99.999% are introduced % argon as the sputtering gas, and Al with a mass percentage greater than 99.999% as the sputtering target, sputtering 200 nm AlN on the graphene to form an AlN nucleation layer. During the sputtering process, the substrate temperature is 700°C, the flow rate of argon gas is 5 sccm, and the flow rate of nitrogen gas is 10 sccm.

Step 4: growing a low temperature GaN transition layer on the upper surface of the AlN nucleation layer;

Specifically, the substrate on which the AlN nucleation layer has grown is placed in a MOCVD vapor deposition reaction chamber, the temperature of the vapor deposition reaction chamber is gradually adjusted to 600° C., and trimethyl gallium is brought in as a Ga source with hydrogen as the carrier gas. Ammonia gas was introduced as an N source, and the pressure in the vapor deposition reaction chamber was kept at 60 Torr; a low-temperature GaN transition layer was grown on the upper surface of the AlN nucleation layer by using MOCVD technology, wherein, during the growth process, the hydrogen flow rate was 2000sccm, and the ammonia flow rate was 2000sccm. The gas flow rate was 5000 sccm, the trimethyl gallium flow rate was 200 sccm, the growth time was 40 minutes, and the thickness of the grown low-temperature GaN transition layer was 200 nm.

Step 5: growing a GaN buffer layer on the upper surface of the low temperature GaN transition layer;

Specifically, the temperature in the MOCVD vapor deposition reaction chamber was adjusted to 1000°C, trimethylgallium was introduced into the MOCVD vapor deposition reaction chamber as a Ga source, and ammonia gas was introduced as an N source at the same time, and the pressure in the vapor deposition reaction chamber was kept as 60 Torr; using MOCVD technology to grow a GaN buffer layer on the upper surface of the low-temperature GaN transition layer, wherein, during the growth process, the flow rate of hydrogen gas is 2000sccm, the flow rate of ammonia gas is 5000sccm, the flow rate of trimethyl gallium is 200sccm, and the growth time is 200 minutes, The thickness of the grown GaN buffer layer was 5 μm.

Step 6: growing an AlGaN barrier layer on the upper surface of the GaN buffer layer;

Specifically, the temperature in the MOCVD vapor deposition reaction chamber was gradually increased to 1100 °C, and hydrogen was used as the carrier gas to bring trimethylgallium and trimethylaluminum as the Ga source and the Al source, respectively, and at the same time, ammonia was introduced as the N source, and keep the pressure in the vapor deposition reaction chamber at 60 Torr, and use MOCVD technology to grow the AlGaN barrier layer on the upper surface of the GaN buffer layer. During the growth process, the flow rate of hydrogen gas is 2000sccm, the flow rate of ammonia The flow rate is 60 sccm, the flow rate of trimethyl aluminum is 1000 sccm, the growth time is 20 minutes, and the thickness of the grown AlGaN barrier layer is 100 nm.

Step 7: Take the slice.

The GaN/AlGaN heterojunction material of the finally formed (110) crystal plane single crystal diamond substrate was taken out from the MOCVD vapor deposition reaction chamber.

Embodiment 4

In this example, a GaN/AlGaN heterojunction comprising a 50 nm AlN nucleation layer, a 100 nm low temperature GaN transition layer, a 2 μm GaN buffer layer and a 50 nm AlGaN barrier layer was prepared by preparing a (111) crystal plane single crystal diamond substrate. Taking the material as an example, the preparation method of the embodiment of the present invention will be described in detail.

The preparation method of this embodiment includes:

Step 1: Select a single crystal diamond substrate;

A single crystal diamond with a thickness of 1 mm and a crystal plane of (111) was selected as the substrate.

Step 2: generating a graphene layer on the upper surface of the (111) single crystal diamond substrate;

Specifically, the graphene layer is grown by chemical vapor deposition on the metal substrate; then the metal substrate covered with the graphene layer is placed in 1 mol/L ferric chloride and 2 mol/L hydrochloric acid to mix at a volume ratio of 1:3 In the mixed solution of 20 hours, the metal substrate is removed; finally, the graphene layer is transferred to the (111) single crystal diamond substrate to obtain the (111) single crystal diamond substrate covered with graphene.

Step 3: using a magnetron sputtering process to grow an AlN nucleation layer on the upper surface of the graphene layer;

Specifically, the (111) crystal plane single crystal diamond substrate covered with the graphene layer obtained in step 2 of this embodiment is placed in a magnetron sputtering system, and nitrogen gas with a mass percentage greater than 99.999% and a mass percentage greater than 99.999% are introduced % argon as the sputtering gas, and Al with a mass percentage greater than 99.999% as the sputtering target, using radio frequency magnetron sputtering, sputtering 50nm on the graphene-covered (100) crystal plane single crystal diamond substrate. AlN, to form an AlN nucleation layer, wherein, in the sputtering process, the substrate temperature is 675° C., the flow rate of argon gas is 5 sccm, and the flow rate of nitrogen gas is 10 sccm.

Step 4: growing a low temperature GaN transition layer on the upper surface of the AlN nucleation layer;

Specifically, the substrate on which the AlN nucleation layer was grown was placed in a MOCVD vapor deposition reaction chamber, the temperature of the vapor deposition reaction chamber was gradually adjusted to 550°C, and trimethyl gallium was brought in as a Ga source by using hydrogen as a carrier gas, and at the same time Ammonia gas was introduced as an N source, and the pressure in the vapor deposition reaction chamber was kept at 50 Torr; a low-temperature GaN transition layer was grown on the upper surface of the AlN nucleation layer by using MOCVD technology, wherein, during the growth process, the flow rate of hydrogen gas was 1000sccm, and the ammonia flow rate was 1000sccm. The gas flow rate is 4000 sccm, the flow rate of trimethyl gallium is 150 sccm, the growth time is 30 minutes, and the thickness of the grown low-temperature GaN transition layer is 100 nm.

Step 5: growing a GaN buffer layer on the upper surface of the low temperature GaN transition layer;

Specifically, the temperature in the MOCVD vapor deposition reaction chamber was adjusted to 950°C, trimethylgallium was introduced into the MOCVD vapor deposition reaction chamber as the Ga source, and ammonia was introduced as the N source, and the pressure in the vapor deposition reaction chamber was kept as 50 Torr; using MOCVD technology to grow a GaN buffer layer on the upper surface of the low-temperature GaN transition layer, wherein the flow rate of hydrogen gas is 1000sccm, the flow rate of ammonia gas is 4000sccm, the flow rate of trimethyl gallium is 150sccm, and the growth time is 100 minutes. The thickness of the layers is 2 μm.

Step 6: growing an AlGaN barrier layer on the upper surface of the GaN buffer layer;

Specifically, the temperature in the MOCVD vapor deposition reaction chamber was gradually increased to 1000 °C, and trimethylgallium and trimethylaluminum were brought in with hydrogen as the carrier gas as the Ga source and the Al source, respectively, and ammonia gas was introduced as the N source, and keep the pressure in the vapor deposition reaction chamber at 50 Torr, and use MOCVD technology to grow the AlGaN barrier layer on the upper surface of the GaN buffer layer. The flow rate of methyl aluminum was 900 sccm, the growth time was 10 minutes, and the thickness of the grown AlGaN barrier layer was 50 nm.

Step 7: Take the slice.

The GaN/AlGaN heterojunction material of the finally formed (111) crystal plane single crystal diamond substrate was taken out from the MOCVD vapor deposition reaction chamber.

Embodiment 5

This embodiment provides a GaN/AlGaN heterojunction material based on a single crystal diamond substrate, including a single crystal diamond substrate 1, a graphene layer 2, an AlN nucleation layer 3, a low temperature GaN transition layer 4, GaN buffer layer 5 and AlGaN barrier layer 6 . In this embodiment, the single crystal diamond substrate 1 , the graphene layer 2 , the AlN nucleation layer 3 , the low-temperature GaN transition layer 4 , the GaN buffer layer 5 and the AlGaN barrier layer 6 can be composed of any of the above-mentioned embodiments. prepared according to the relevant steps in this example. The heterojunction material can be used in the fields of high temperature, high current and high power devices

Further, in this embodiment, the crystal plane of the single crystal diamond substrate (1) is (100) or (110) or (111). The thickness of the single crystal diamond substrate is 0.3-1mm, the thickness of the graphene is 0.2-0.4nm, the thickness of the AlN nucleation layer is 20-100nm, and the thickness of the low temperature GaN transition layer is 20-200nm , the thickness of the GaN buffer layer is 0.1-5 μm, and the thickness of the AlGaN barrier layer is 5-100 nm.

The GaN/AlGaN heterojunction material based on the single crystal diamond substrate of this embodiment transfers a layer of graphene on the single crystal diamond substrate, and grows an AlN nucleation layer on the graphene layer, so that high quality can be grown on the graphene. In addition, the GaN/AlGaN heterojunction material based on the single crystal diamond substrate of this embodiment has the advantages of good heat dissipation, high quality, simple process, and low cost.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (10)

1. a preparation method based on the GaN/AlGaN heterojunction material of single crystal diamond substrate, is characterized in that, comprises: S1: select a single crystal diamond substrate; S2: generating a graphene layer on the upper surface of the single crystal diamond substrate; S3: growing an AlN nucleation layer on the upper surface of the graphene layer; S4: growing a low temperature GaN transition layer on the upper surface of the AlN nucleation layer; S5: growing a GaN buffer layer on the upper surface of the low-temperature GaN transition layer; S6: growing an AlGaN barrier layer on the upper surface of the GaN buffer layer, thereby forming a GaN/AlGaN heterojunction material based on a single crystal diamond substrate. 2. preparation method according to claim 1, is characterized in that, described S1 comprises: A single crystal diamond with a thickness of 0.3-1 mm and a crystal plane of (100) or (110) or (111) is selected as the substrate. 3. preparation method according to claim 2, is characterized in that, described S2 comprises: S21: growing a graphene layer with a thickness of 0.2-0.4 nm on a metal substrate; S22: chemically corrode the metal substrate covered with the graphene layer to remove the metal substrate; S23: Transfer the graphene layer to the single crystal diamond substrate to obtain a single crystal diamond substrate covered with a graphene layer. 4. preparation method according to claim 1, is characterized in that, described S3 comprises: S31: select Al with a mass percentage greater than 99.999% as the sputtering target; S32: Select nitrogen with a mass percentage greater than 99.999% and argon with a mass percentage greater than 99.999% as the sputtering gas, and pass the two kinds of sputtering gases into the sputtering chamber at the same time; S33: Sputtering is performed on the upper surface of the graphene layer by using a magnetron sputtering technology to generate an AlN nucleation layer. 5. preparation method according to claim 1, is characterized in that, described S4 comprises: S41: use trimethyl gallium as the Ga source and ammonia as the N source, and simultaneously pass into the gas-phase precipitation reaction chamber; S42: Under the conditions that the pressure of the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature is 450-600° C., the flow rate of ammonia gas is 3000-5000 sccm, and the flow rate of trimethyl gallium is 100-200 sccm, using metal organic compound chemical vapor deposition The technique grows a low temperature GaN transition layer on the upper surface of the AlN nucleation layer. 6. preparation method according to claim 1, is characterized in that, described S5 comprises: S51: use trimethyl gallium as the Ga source and ammonia as the N source, and simultaneously pass into the gas-phase precipitation reaction chamber; S52: Under the conditions that the pressure of the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature is 900-1000° C., the flow rate of ammonia gas is 3000-5000 sccm, and the flow rate of trimethyl gallium is 100-200 sccm, using metal organic compound chemical vapor deposition technology grows a GaN buffer layer on the upper surface of the low temperature GaN transition layer. 7. preparation method according to claim 1, is characterized in that, described S6 comprises: S61: use trimethyl gallium as the Ga source, trimethyl aluminum as the Al source, and ammonia as the N source, and simultaneously pass into the vapor deposition reaction chamber; S62: The pressure in the vapor deposition reaction chamber is 40-60 Torr, the substrate temperature range is 1000-1100 ℃, the flow rate of ammonia gas is 3000-5000 sccm, the flow rate of trimethyl gallium is 30-60 sccm, and the flow rate of trimethyl aluminum is 800-1000 sccm The AlGaN barrier layer is grown on the upper surface of the GaN buffer layer by using the metal organic compound chemical vapor deposition technology under the conditions of the present invention. 8. A GaN/AlGaN heterojunction material based on a single crystal diamond substrate prepared by the preparation method according to any one of claims 1 to 7, wherein the single crystal diamond substrate is sequentially included from bottom to top (1), a graphene layer (2), an AlN nucleation layer (3), a low temperature GaN transition layer (4), a GaN buffer layer (5) and an AlGaN barrier layer (6). 9. The GaN/AlGaN heterojunction material based on a single crystal diamond substrate according to claim 8, wherein the crystal plane of the single crystal diamond substrate (1) is (100) or (110) or (111). 10. The GaN/AlGaN heterojunction material based on a single crystal diamond substrate according to claim 9, wherein the single crystal diamond substrate (1) has a thickness of 0.3-1 mm, and the graphene layer has a thickness of 0.3-1 mm. The thickness of (2) is 0.2-0.4 nm, the thickness of the AlN nucleation layer (3) is 20-100 nm, the thickness of the low temperature GaN transition layer (4) is 20-200 nm, the thickness of the GaN buffer layer (5) ) is 0.1-5 μm thick, and the AlGaN barrier layer (6) has a thickness of 5-100 nm.

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