CN111933513A - Method for preparing nitride semiconductor material - Google Patents

Abstract

The present invention provides a method for preparing a nitride semiconductor material, which includes the following steps: (1) forming a high absorption layer on a surface of a substrate; (2) forming a high absorption layer on or with the high absorption layer On the other surface of the opposite substrate, a nitride semiconductor material is deposited by means of microwave heating; the high absorption layer is formed of a material having a dielectric loss factor not lower than 0.01. By the method of the present invention, uniform heat conduction to the nitride semiconductor material can be achieved. Meanwhile, the method of the present invention has higher energy utilization efficiency. In the method of the present invention, the energy is absorbed by the material to be heated, and the cavity of the vacuum deposition equipment is not heated, which is beneficial to prolong the maintenance and use of the equipment.

Description

Preparation method of nitride semiconductor material

technical field

The present invention relates to the field of semiconductor materials. Specifically, the present invention relates to a method for preparing a nitride semiconductor material.

Background technique

With the advancement of semiconductor production and manufacturing technology, as well as the advancement of science and technology and the development of society, the application fields of semiconductors are becoming more and more extensive, and the requirements for the performance of semiconductors are also getting higher and higher. Semiconductor materials not only have great applications in the field of optoelectronics, but also the cornerstone of the field of power electronics. Especially III-V semiconductor materials.

A high temperature process must be experienced during the growth of the semiconductor material, and even after the structure growth is completed, to achieve the final function. The high temperature process serves the purpose of promoting material growth, activating elements, and releasing stress. At present, in material growth equipment (such as MOCVD, MBE), resistance wire heating or infrared heating methods are mainly used. The strength of the resistance wire in the high temperature environment is low, and the plasticity of the heating wire will increase as the temperature increases, and it is easy to deform at high temperature, and it is not easy to repair after deformation. The reaction of infrared heating is too fast, and the temperature rises too quickly.

The main advantages of microwave heating include: instantaneous application and removal of energy; direct heating of the material rather than conduction, where both the interior and the surface of the material are heated simultaneously; and selective heating, which allows heating of the grown structure individually rather than the entire The heating of the cavity of the device makes the growth of materials easier. For example, when growing gallium nitride on sapphire, since the microwave only heats the gallium nitride and not the sapphire, the thermal stress can be controlled more easily. Moreover, since the whole gallium nitride material can absorb microwave energy, the gallium nitride material can be heated more uniformly.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the prior art, the present invention provides a new method for preparing nitride semiconductor materials. The novel method for preparing the nitride semiconductor material of the present invention adopts microwave heating. By the method of the present invention, uniform heat conduction to the nitride semiconductor material can be achieved. Meanwhile, the method of the present invention has higher energy utilization efficiency.

The above objects of the present invention are achieved through the following technical solutions.

The present invention provides a method for preparing a nitride semiconductor material, comprising the following steps:

(1) forming a high absorption layer on one surface of the substrate;

(2) on the high absorption layer or on the other surface of the substrate opposite to the high absorption layer, by means of microwave heating, depositing a nitride semiconductor material;

The high absorption layer is formed of a material having a dielectric loss factor of not less than 0.01.

Preferably, in the method of the present invention, the substrate is a sapphire, silicon or silicon carbide substrate.

Preferably, in the method of the present invention, the high absorption layer is formed by one or more of GaO, ZnO, TiO ₂ and compounds of the formula Al _x Ga _(1-x) N, wherein 0≤x ≤1.

Preferably, in the method of the present invention, the high absorption layer is formed of GaN and/or AlN.

Preferably, in the method of the present invention, the thickness of the high absorption layer is 50 nm-2 μm.

Preferably, in the method of the present invention, the formation of the high absorption layer in the step (1) is performed by physical or chemical deposition.

Preferably, in the method of the present invention, the physical or chemical deposition is performed by sputtering, evaporation, chemical vapor deposition, atomic layer deposition or molecular beam epitaxy.

Preferably, in the method of the present invention, the method further comprises, after the step (1) and before the step (2), the step of patterning the high absorption layer.

Preferably, in the method of the present invention, the microwave heating is performed under the following conditions: the frequency of the microwave heating source is controlled to be 2GHz-20GHz in the vacuum deposition chamber.

Beneficial effects of the present invention:

(1) The method of the present invention has a wide range of application: in the present invention, the nitride semiconductor materials include but are not limited to III-V group semiconductor materials and metal oxide semiconductor materials. For example, a gallium nitride-based LED structure, a gallium nitride-based HEMT structure or a gallium nitride-based detector structure can be fabricated by using the method of the present invention.

(2) The method of the present invention can achieve uniform heat conduction to the nitride semiconductor material by virtue of the high absorption effect of the high absorption layer on microwaves. Meanwhile, the method of the present invention has higher energy utilization efficiency. In the method of the present invention, the energy is absorbed by the material to be heated, and the cavity of the vacuum deposition equipment is not heated, which is beneficial to prolong the maintenance and use of the equipment.

Description of drawings

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein:

Fig. 1 is the flow chart of the method of embodiment 1 of the present invention;

Fig. 2 is the flow chart of the method of embodiment 2 of the present invention;

Fig. 3 is the flow chart of the method of embodiment 3 of the present invention;

Fig. 4 is the flow chart of the method of embodiment 4 of the present invention;

5 is a schematic cross-sectional view of the structure of a nitride semiconductor material prepared on a high absorption layer by microwave heating according to Embodiment 1 of the present invention;

6 is a schematic cross-sectional view of the structure of a nitride semiconductor material prepared on a patterned high absorption layer by microwave heating according to Embodiment 2 of the present invention;

7 is a schematic cross-sectional view of the structure of the nitride semiconductor material prepared on the other surface of the substrate opposite to the high absorption layer by microwave heating according to Embodiment 3 of the present invention;

8 is a schematic cross-sectional view of the structure of a nitride semiconductor material prepared on a high absorption layer by microwave heating according to Embodiment 4 of the present invention;

Fig. 9 is the SEM scanning diagram of the material section prepared by Example 4 of the present invention;

Fig. 10 is the AFM scanning diagram of the material prepared by Example 4 of the present invention;

11 is the current-voltage characteristic of the LED device prepared from the structure grown in Example 4 of the present invention;

Among them, the reference numerals are as follows:

1 substrate

2 high absorption layers

3 Nitride semiconductor materials.

Detailed ways

The present invention will be further described in detail below with reference to the specific embodiments, and the given examples are only for illustrating the present invention, rather than for limiting the scope of the present invention.

Example 1

This embodiment relates to a method for preparing a nitride semiconductor material by microwave heating. The specific process is shown in FIG. 1 , which includes the following steps:

(1) Provide the 2-inch sapphire substrate required for growth;

(2) growing a layer of aluminum nitride (AlN) on one surface of the substrate;

The AlN material is prepared by sputtering, the substrate temperature is 200℃, the flow ratio of N ₂ /Ar is 1:2, the working pressure is 0.1Pa, and the thickness of the grown AlN material is 100nm;

(3) On the AlN material, in a MOCVD chamber with a vacuum degree of 400 mbar, microwave heating is used to prepare a nitride semiconductor material to form a GaN-based LED;

In the process of growing the nitride semiconductor material, the AlN layer is heated with not less than one microwave emitting source, the frequency of the microwave source is 2.4GHz, and the AlN is heated to 1150°C for the growth of the nitride semiconductor material. With the high absorption effect of AlN on microwaves, on the one hand, uniform heat conduction to the nitride semiconductor material is ensured, which overcomes the problem of low non-contact efficiency; on the other hand, because the area of AlN corresponds to the nitride semiconductor material, the energy efficiency is improved. usage efficiency. A GaN buffer layer of about 600nm thickness was first grown on the AlN surface; then the substrate was heated to 1050°C by microwave; then 4um of N-type GaN was deposited, followed by cooling the substrate to 800°C, and then GaN/InGaN multiple quantum wells were deposited structure; next, the temperature is raised to 900°C, and P-type Mg-doped GaN is grown on the surface of the quantum well to complete the growth of the structure. FIG. 5 is a schematic cross-sectional view of the structure of the nitride semiconductor material prepared on the high absorption layer by microwave heating according to the present embodiment.

Example 2

This embodiment relates to a method for preparing a semiconductor material by microwave heating. The specific process is shown in FIG. 2, which includes the following steps:

(1) Provide a 2-inch silicon substrate required for growth;

(2) growing a layer of aluminum nitride (AlN) material on one surface of the substrate;

The AlN material is prepared by sputtering, the substrate temperature is 200℃, the flow ratio of N ₂ /Ar is 1:2, the working pressure is 0.1Pa, and the thickness of the grown AlN material is 1.5μm;

(3) patterning the aluminum nitride material;

Using methods such as UV exposure or nano-imprinting, a photoresist pattern with a periodic structure is prepared, and then the pattern is transferred to AlN by etching to prepare a pattern with a depth of 100 nm;

(4) On the AlN material, in a MOCVD chamber with a vacuum degree of 400 mbar, microwave heating is used to prepare a nitride semiconductor material to form a GaN-based LED;

In the process of growing the nitride semiconductor material, the aluminum nitride layer is heated with no less than one microwave emission source, and the microwave power is 6.5GHz, and the growth of the nitride semiconductor material is carried out by heating the AlN to 1150°C. With the high absorption effect of AlN on microwaves, on the one hand, the uniform heat conduction to the nitride semiconductor material is ensured, which overcomes the problem of low efficiency of non-contact; energy efficiency. A GaN buffer layer of about 500nm thickness was first grown on the AlN surface; then the substrate was heated to 1050°C by microwave; then 4um of N-type GaN was deposited, then the substrate was cooled to 800°C, and then GaN/InGaN multiple quantum wells were deposited structure; next, the temperature is raised to 900°C, and P-type Mg-doped GaN is grown on the surface of the quantum well to complete the growth of the structure. 6 is a schematic cross-sectional view of the structure of the nitride semiconductor material prepared on the patterned high absorption layer by microwave heating according to the present embodiment.

Example 3

This embodiment relates to a method for preparing a semiconductor material by microwave heating. The specific process is shown in FIG. 3 , which includes the following steps:

(1) Provide the 2-inch sapphire substrate required for growth;

(2) growing a layer of titanium dioxide (TiO ₂ ) on one surface of the substrate;

The TiO ₂ material was prepared by sputtering, the substrate temperature was 200°C, the N ₂ /Ar flow ratio was 1:2, the working pressure was 0.1Pa, and the thickness of the grown TiO ₂ material was 100 nm;

(3) On the other surface of the substrate opposite to the titanium dioxide, in a MOCVD chamber with a vacuum degree of 400 mbar, microwave heating is used to prepare a nitride semiconductor material to form a GaN-based LED;

In the process of growing the nitride semiconductor material, the titanium dioxide layer is heated with no less than one microwave emission source, and the microwave frequency is 16GHz, and the growth of the nitride semiconductor material is carried out by specifically heating the titanium dioxide to 1150°C. By virtue of the high absorption effect of titanium dioxide on microwaves, on the one hand, uniform heat conduction to the nitride semiconductor material is ensured; on the other hand, because the area of titanium dioxide corresponds to the nitride semiconductor material, the energy utilization efficiency is improved. First, a GaN buffer layer with a thickness of about 700 nm is grown on the surface of the substrate opposite to the titania; then the substrate is heated to 1050°C by microwave; then 4um of N-type GaN is deposited, then the substrate is cooled to 800°C, and then GaN is deposited /InGaN multi-quantum well structure; next, the temperature is raised to 900°C, and P-type Mg-doped GaN is grown on the surface of the quantum well to complete the growth of the structure. 7 is a schematic cross-sectional view of the structure of the nitride semiconductor material prepared on the other surface of the substrate opposite to the high absorption layer by microwave heating in this embodiment.

Example 4

This embodiment relates to a method for preparing a semiconductor material by microwave heating. The specific process is shown in FIG. 4 , which includes the following steps:

(1) Provide the 2-inch sapphire substrate required for growth;

(2) growing a layer of GaN material on one surface of the substrate;

The GaN material is grown by means of resistance heating, the substrate is heated to 1150°C by means of resistance wire heating, and the GaN buffer layer is grown in a MOCVD chamber with a vacuum degree of 400mbar, and the thickness of the grown GaN material is 200nm;

(3) On the GaN material, in a MOCVD chamber with a vacuum degree of 400 mbar, microwave heating is used to prepare a nitride semiconductor material to form a GaN-based LED;

During the growth of the nitride semiconductor material, the GaN buffer layer is heated with no less than one microwave emission source, and the microwave frequency is 2.56 GHz, and the growth of the nitride semiconductor material is carried out by heating the GaN to a suitable temperature. With the high absorption effect of GaN on microwaves, on the one hand, the uniform heat conduction to the nitride semiconductor material is ensured, which overcomes the problem of low efficiency of non-contact; on the other hand, because the area of aluminum nitride corresponds to the nitride semiconductor material, the increase energy efficiency. The substrate was heated to 1050°C by microwave; then 4um of N-type GaN was deposited, then the substrate was cooled to 800°C, and then the GaN/InGaN multiple quantum well structure was deposited; then the temperature was raised to 900°C, on the surface of the quantum well Growth of P-type Mg-doped GaN completes the growth of the structure. FIG. 8 is a schematic cross-sectional view of the structure of the nitride semiconductor material prepared on the high absorption layer by microwave heating in this embodiment. FIG. 9 is a SEM scanning image of the cross section of the material prepared in this example. Figure 9 shows a clear layered structure and a clear interface between the nitride semiconductor material and the sapphire substrate. FIG. 10 is an AFM scan of the material prepared in this example. Figure 10 shows that the morphology of the surface of the prepared material conforms to that of a normal nitride material. FIG. 11 shows the current-voltage characteristics of the LED device prepared by using the structure grown in this embodiment. It can be seen that the LED device prepared by the present invention has normal performance.

Claims (9)

1. A method of preparing a nitride semiconductor material, comprising the steps of:

(1) forming a high absorption layer on one surface of a substrate;

(2) depositing a nitride semiconductor material by means of microwave heating on the highly absorbing layer or on another surface of the substrate opposite to the highly absorbing layer;

the high absorption layer is formed of a material having a dielectric loss tangent of not less than 0.01.

2. The method of claim 1, wherein the substrate is a sapphire, silicon, or silicon carbide substrate.

3. The method of claim 1, wherein the high absorption layer is made of GaO, ZnO, TiO₂And formula Al_xGa_(1-x)One or more of N compounds, wherein x is more than or equal to 0 and less than or equal to 1.

4. The method of claim 3, wherein the high absorption layer is formed of GaN and/or AlN.

5. The method of claim 1, wherein the thickness of the high absorption layer is 50nm-2 μ ι η.

6. The method according to claim 1, wherein the forming of the high absorption layer in the step (1) is performed by physical or chemical deposition.

7. The method of claim 6, wherein the physical or chemical deposition is by sputtering, evaporation, chemical vapor deposition, atomic layer deposition, or molecular beam epitaxy deposition.

8. The method of claim 1, further comprising, after step (1) and before step (2), the step of patterning the superabsorbent layer.

9. The method of claim 1, wherein the microwave heating is performed under the following conditions: the frequency of the microwave heating source is controlled to be 2GHz-20GHz in the vacuum deposition chamber.

Images