Methods for growing gallium nitride layers on a substrate surface, applications, and gallium nitride semiconductor materials

Abstract

The application discloses a method for growing a gallium nitride layer on a substrate surface, application and gallium nitride semiconductor material, and relates to the technical field of semiconductors. The method comprises the following steps: depositing an aluminum nitride buffer layer on the substrate surface at low temperature by using a magnetron sputtering technology, wherein the thickness of the aluminum nitride buffer layer is 10-20 nm; and forming an aluminum nitride layer and a gallium nitride layer on the surface of the aluminum nitride buffer layer in sequence by using a MOCVD process at high temperature. x By using the method combining the low-temperature deposition of the magnetron sputtering and the high-temperature epitaxy of the MOCVD, on one hand, the generation of the SiN interface layer can be overcome, and a qualified gallium nitride film can be grown; on the other hand, the combination of the two methods forms an island-shaped nucleation layer in the deposition process, and the island-shaped nucleation layer can help release the film stress, thereby improving the material quality.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a method for growing a gallium nitride layer on a substrate surface, its application, and gallium nitride semiconductor materials. Background Technology

[0002] Gallium nitride (GaN), a third-generation wide-bandgap semiconductor, possesses characteristics such as high electron mobility, high cutoff voltage, good physicochemical stability, high electron saturation velocity, and steep absorption band edge, making it an ideal material for manufacturing devices such as light-emitting diodes (LEDs), laser diodes (LDs), and photodetectors.

[0003] In recent years, Si substrates have been widely used in the epitaxial fabrication of nitride thin films due to their advantages such as low cost, large size, and high thermal stability. Currently, most nitride thin films on Si substrates are prepared using metal-organic chemical vapor deposition (MOCVD). Furthermore, to mitigate the impact of the large lattice mismatch between gallium nitride (GaN) and Si, an aluminum nitride buffer layer is typically introduced between the GaN and Si substrates to reduce defects in the thin film.

[0004] However, MOCVD is a high-temperature growth technique, with growth temperatures exceeding 1000℃. Due to the significant thermal expansion coefficient mismatch and lattice mismatch between gallium nitride (GaN) and the Si substrate, numerous defects and cracks are introduced into the epitaxial film during growth and cooling, greatly reducing the performance of the GaN film. Furthermore, under the high-temperature growth environment, an interfacial reaction occurs between the nitride and the Si substrate, forming SiN on the epitaxial surface. x The interface layer can lead to problems such as epitaxial growth failure or poor quality of epitaxial thin film crystals.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for growing a gallium nitride layer on a substrate surface, its application, and gallium nitride semiconductor materials.

[0007] This invention is implemented as follows:

[0008] In a first aspect, the present invention provides a method for growing a gallium nitride layer on a substrate surface, comprising using magnetron sputtering to deposit an aluminum nitride buffer layer on the substrate surface at low temperature, the aluminum nitride buffer layer having a thickness of 10-20 nm, and using MOCVD process to epitaxially form an aluminum nitride layer and a gallium nitride layer sequentially on the surface of the aluminum nitride buffer layer at high temperature.

[0009] In an optional embodiment, the parameters for magnetron sputtering deposition of the aluminum nitride buffer layer include: RF power of 80–100 W, argon pressure of 3–6 mTorr, growth temperature of 25–200 °C, substrate rotation speed of 10–20 rpm, and background vacuum of 1 × 10⁻⁶ mTorr in the reaction chamber. -9 ~1×10 -8 Torr.

[0010] In an optional embodiment, the parameters for magnetron sputtering deposition of the aluminum nitride buffer layer include: RF power of 80–90 W, argon pressure of 3–5 mTorr, growth temperature of 150–200 °C, substrate rotation speed of 15–20 rpm, and background vacuum of 1 × 10⁻⁶ mT₀ / mT₀. -9 ~1×10 -8 Torr.

[0011] In an optional embodiment, the MOCVD process parameters for forming the aluminum nitride layer include: substrate temperature of 1030–1050°C, rotation speed of 1200–1500 r / min, nitrogen gas pressure of 50–80 Torr, and N / Al ratio of 500–1000.

[0012] Preferably, the thickness of the aluminum nitride layer is 30–50 nm.

[0013] In an optional embodiment, the MOCVD process parameters for forming the gallium nitride layer include: substrate temperature of 1000–1100°C, rotation speed of 1000–1500 r / min, nitrogen gas pressure of 200–500 Torr, and N / Ga ratio of 500–5000.

[0014] Preferably, the thickness of the gallium nitride layer is 200–3000 nm.

[0015] In an optional implementation, the number of gallium nitride layers is 1 to 3.

[0016] In an optional embodiment, the substrate is further cleaned and dried before magnetron sputtering.

[0017] Preferably, the cleaning includes ultrasonic cleaning, in which the solvent used for ultrasonic cleaning is acetone or anhydrous ethanol, the ultrasonic time is 5 to 10 minutes, the ultrasonic power is 80 to 90 W, and the ultrasonic cleaning is performed 2 to 3 times.

[0018] Preferably, drying is performed by blowing with nitrogen gas.

[0019] In an optional embodiment, the substrate is a silicon-based substrate.

[0020] In a second aspect, the present invention provides a gallium nitride semiconductor material, which is prepared by any of the methods described in the foregoing embodiments, comprising a substrate and an aluminum nitride buffer layer, an aluminum nitride layer and a gallium nitride layer sequentially formed on the surface of the substrate.

[0021] Thirdly, the present invention provides the application of the method as described in any of the foregoing embodiments in the preparation of semiconductor materials.

[0022] The present invention has the following beneficial effects:

[0023] This invention provides a method for growing a gallium nitride layer on a substrate surface, its application, and gallium nitride semiconductor materials. By employing a combination of low-temperature magnetron sputtering deposition and high-temperature MOCVD epitaxy, it is advantageous in overcoming the limitations of SiN... x The formation of the interface layer results in the growth of a qualified gallium nitride thin film. On the other hand, the combination of the above two methods forms an island-shaped nucleus layer during the deposition process. The use of the island-shaped nucleus layer can help release the film stress, thereby improving the material quality. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a gallium nitride semiconductor material provided in an embodiment of the present invention;

[0026] Figure 2 An optical micrograph of a gallium nitride layer provided in Embodiment 1 of the present invention;

[0027] Figure 3 An optical micrograph of a gallium nitride layer provided in Comparative Example 1 of this invention;

[0028] Figure 4 An optical microscopic image of a gallium nitride layer provided in Comparative Example 2 of this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0031] In a first aspect, the present invention provides a method for growing a gallium nitride layer on a substrate surface, comprising using magnetron sputtering to deposit an aluminum nitride buffer layer on the substrate surface at low temperature, the aluminum nitride buffer layer having a thickness of 10-20 nm, and using MOCVD process to epitaxially form an aluminum nitride layer and a gallium nitride layer sequentially on the surface of the aluminum nitride buffer layer at high temperature.

[0032] By combining low-temperature magnetron sputtering deposition with high-temperature MOCVD epitaxy, it is beneficial to overcome the challenges of SiN... x The formation of the interface layer results in the growth of a qualified gallium nitride thin film. On the other hand, the combination of the above two methods forms an island-shaped nucleus layer during the deposition process. The use of the island-shaped nucleus layer can help release the film stress, thereby improving the material quality.

[0033] In an optional embodiment, the parameters for magnetron sputtering deposition of the aluminum nitride buffer layer include: RF power of 80–100 W, argon pressure of 3–6 mTorr, growth temperature of 25–200 °C, substrate rotation speed of 10–20 rpm, and background vacuum of 1 × 10⁻⁶ mTorr in the reaction chamber. -9 ~1×10 -8 Torr.

[0034] In an optional embodiment, the parameters for magnetron sputtering deposition of the aluminum nitride buffer layer include: RF power of 80–90 W, argon pressure of 3–5 mTorr, growth temperature of 150–200 °C, substrate rotation speed of 15–20 rpm, and background vacuum of 1 × 10⁻⁶ mT₀ / mT₀. -9 ~1×10 -8 Torr.

[0035] By controlling the magnetron sputtering parameters within the above range, an aluminum nitride buffer layer with strong adhesion to the substrate can be obtained, which is beneficial to the subsequent growth of gallium nitride layers. This avoids the large thermal expansion coefficient mismatch and lattice mismatch between gallium nitride and the Si substrate, which would introduce a large number of defects and cracks into the epitaxial film during the growth and cooling process.

[0036] In an optional embodiment, the MOCVD process parameters for forming the aluminum nitride layer include: substrate temperature of 1030–1050°C, rotation speed of 1200–1500 r / min, nitrogen gas pressure of 50–80 Torr, and N / Al ratio of 500–1000.

[0037] Preferably, the thickness of the aluminum nitride layer is 30–50 nm.

[0038] In an optional embodiment, the MOCVD process parameters for forming the gallium nitride layer include: substrate temperature of 1000–1100°C, rotation speed of 1000–1500 r / min, nitrogen gas pressure of 200–500 Torr, and N / Ga ratio of 500–5000.

[0039] Preferably, the thickness of the gallium nitride layer is 200–3000 nm.

[0040] In an optional implementation, the number of gallium nitride layers can be set to one or more layers as needed. When multiple layers are used, the structure of each gallium nitride layer can be the same or different, depending on the specific product requirements, as long as the process parameters are within the above range.

[0041] In an optional embodiment, in order to grow the gallium nitride layer better and obtain a gallium nitride layer with no surface defects, the substrate is further cleaned and dried before magnetron sputtering to remove oil and impurities from the substrate surface.

[0042] Preferably, the cleaning includes ultrasonic cleaning, in which the solvent used for ultrasonic cleaning is acetone or anhydrous ethanol, the ultrasonic time is 5 to 10 minutes, the ultrasonic power is 80 to 90 W, and the ultrasonic cleaning is performed 2 to 3 times.

[0043] Preferably, drying is performed by blowing with nitrogen gas.

[0044] In an optional embodiment, the substrate is a silicon-based substrate.

[0045] In a second aspect, the present invention provides a gallium nitride semiconductor material, which is prepared by any of the methods described in the foregoing embodiments, comprising a substrate and an aluminum nitride buffer layer, an aluminum nitride layer and a gallium nitride layer sequentially formed on the surface of the substrate.

[0046] Thirdly, the present invention provides the application of the method as described in any of the foregoing embodiments in the preparation of semiconductor materials.

[0047] Example 1

[0048] This embodiment provides a method for growing a gallium nitride layer on a substrate surface, including the following steps:

[0049] S01. Cleaning and drying

[0050] Place the card slot containing the substrate into a clean beaker, add anhydrous ethanol until the solution completely submerges the substrate, and sonicate for 10 minutes at an ultrasonic power of 90W. Repeat the above steps, and then sonicate three times with deionized water until the organic solution is removed, and then blow dry with nitrogen.

[0051] S02, Preparation of aluminum nitride buffer layer

[0052] An aluminum nitride buffer layer is formed on the substrate surface using magnetron sputtering technology. The magnetron sputtering process includes placing the substrate in a pre-vacuum chamber, then transferring it into the deposition chamber by a robotic arm, and using a substrate RF bias power supply to excite argon glow discharge to generate Ar. + Plasma bombardment of aluminum nitride target produces deposited particles, forming an aluminum nitride buffer layer on the substrate surface.

[0053] The magnetron sputtering process features an RF power of 80W, an argon pressure of 3mTorr, a growth temperature of 200℃, and a substrate rotation speed of 20rpm; the deposition chamber has a base vacuum of 1×10⁻⁶. -9 Torr.

[0054] The prepared aluminum nitride buffer layer has a thickness of 20 nm.

[0055] S03, Preparation of aluminum nitride layer

[0056] An aluminum nitride layer was epitaxially formed on an aluminum nitride buffer layer using MOCVD technology at high temperature. The parameters of the MOCVD process included: substrate temperature of 1030℃, rotation speed of 1200 r / min, growth gas pressure of 50 Torr, and N / Al ratio of 1000.

[0057] The thickness of the prepared aluminum nitride layer is 30–50 nm.

[0058] S04, growth of gallium nitride layer

[0059] Gallium nitride (GaN) layers were epitaxially formed on aluminum nitride (ANT) thin films at high temperatures using MOCVD (Metal-Oxide-Chip Vapor Deposition) technology. The MOCVD process parameters included: substrate temperature of 1000℃, rotation speed of 1000 r / min, growth gas pressure of 200 Torr, and N / Ga ratio of 5000.

[0060] The thickness of the prepared gallium nitride layer is 2000 nm.

[0061] like Figure 1 As shown, the gallium nitride semiconductor material prepared in this embodiment includes a substrate 11, and aluminum nitride buffer layer 12, aluminum nitride layer 13, and gallium nitride layer 14 grown on its surface. When the above material is observed under an optical microscope, the following results are obtained: Figure 2 The results are shown. (From...) Figure 2 As can be seen, the gallium nitride layer provided in this embodiment has a smooth and defect-free surface, and thus has high film quality.

[0062] Example 2

[0063] This embodiment provides a method for growing a gallium nitride layer on a substrate surface, including the following steps:

[0064] S01. Cleaning and drying

[0065] Place the card slot containing the substrate into a clean beaker, add acetone until the solution completely submerges the substrate, and sonicate for 5 minutes at an ultrasonic power of 90W. Repeat the above steps, and then sonicate twice with deionized water until the organic solution is removed, and then blow dry with nitrogen.

[0066] S02, Preparation of aluminum nitride buffer layer

[0067] An aluminum nitride buffer layer is formed on the substrate surface using magnetron sputtering technology. The magnetron sputtering process includes placing the substrate in a pre-vacuum chamber, then transferring it into the deposition chamber by a robotic arm, and using a substrate RF bias power supply to excite argon glow discharge to generate Ar. + Plasma bombardment of aluminum nitride target produces deposited particles, forming an aluminum nitride buffer layer on the substrate surface.

[0068] The magnetron sputtering process features an RF power of 100W, an argon pressure of 6 mTorr, a growth temperature of 25℃, and a substrate rotation speed of 10 rpm; the deposition chamber has a base vacuum of 1×10⁻⁶. -8 Torr.

[0069] The prepared aluminum nitride buffer layer has a thickness of 20 nm.

[0070] S03, Preparation of aluminum nitride layer

[0071] An aluminum nitride layer was epitaxially formed on an aluminum nitride buffer layer using MOCVD technology at high temperature. The parameters of the MOCVD process included: substrate temperature of 1050℃, rotation speed of 1500 r / min, growth gas pressure of 80 Torr, and N / Al ratio of 1000.

[0072] The thickness of the prepared aluminum nitride layer is 50 nm.

[0073] S04, growth of gallium nitride layer

[0074] Gallium nitride (GaN) layers were epitaxially formed on aluminum nitride (ANT) films at high temperatures using MOCVD (Metal-Oxide-Chip Vapor Deposition) technology. The MOCVD process parameters included: substrate temperature of 1100°C, rotation speed of 1500 r / min, growth gas pressure of 500 Torr, and N / Ga ratio of 5000.

[0075] The thickness of the prepared gallium nitride layer is 1000 nm.

[0076] Comparative Example 1

[0077] This comparative example provides a method for growing a gallium nitride layer on a substrate surface. The specific steps are similar to those in Example 1, except that the S02 step is not included.

[0078] Comparative Example 2

[0079] This comparative example provides a method for growing a gallium nitride layer on a substrate surface. The specific steps are similar to those in Example 1, except that the thickness of the aluminum nitride buffer layer prepared by magnetron sputtering is 50 nm.

[0080] The gallium nitride layers prepared in Comparative Examples 1 and 2 were observed under an optical microscope, and the results were as follows: Figure 3 and 4 The results are shown in the figure. As can be seen from the figure, the gallium nitride layer provided in this comparative example has a large number of black spot defects on its surface, resulting in poor film quality, and several fine cracks appear in the film.

[0081] Experimental Example 1

[0082] The gallium nitride coatings prepared in Example 1 and Comparative Examples 1-2 were subjected to crystal quality testing. The testing method was to measure the full width at half maximum (FWHM) of the XRD rocking curves of GaN(0002) and GaN(10-12) crystal planes, and the results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] As shown in Table 1, the full width at half maximum (FWHM) of the XRD rocking curves of GaN(0002) and GaN(10-12) crystal planes in Comparative Examples 1 and 2 is much larger than that in Example 1, indicating that there are a large number of dislocation defects in their crystals and poor crystal quality.

[0087] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for growing a gallium nitride layer on a substrate surface, characterized in that, The method includes using magnetron sputtering to deposit an aluminum nitride buffer layer on a substrate surface at low temperature, wherein the thickness of the aluminum nitride buffer layer is 10~20nm, and using MOCVD process to epitaxially form an aluminum nitride layer and a gallium nitride layer on the surface of the aluminum nitride buffer layer at high temperature. The parameters for magnetron sputtering deposition of aluminum nitride buffer layers include: RF power of 80~100W, argon pressure of 3~6 mTorr, growth temperature of 25~200℃, substrate rotation speed of 10~20 rpm, and background vacuum of 1×10⁻⁶ mTorr in the reaction chamber. -9 ~1×10 -8 Torr; The MOCVD process parameters for forming the aluminum nitride layer include: substrate temperature of 1030~1050℃, rotation speed of 1200~1500r / min, nitrogen gas pressure of 50~80 Torr, and N / Al ratio of 500~1000. The thickness of the aluminum nitride layer is 30~50nm.

2. The method according to claim 1, characterized in that, The parameters for magnetron sputtering deposition of aluminum nitride buffer layers include: RF power of 80-90W, argon pressure of 3-5 mTorr, growth temperature of 150-200℃, substrate rotation speed of 15-20 rpm, and background vacuum of 1×10⁻⁶ mT⁻¹ in the reaction chamber. -9 ~1×10 -8 Torr.

3. The method according to claim 2, characterized in that, The MOCVD process parameters for forming the gallium nitride layer include: substrate temperature of 1000~1100℃, rotation speed of 1000~1500 r / min, nitrogen gas pressure of 200~500 Torr, and N / Ga ratio of 500~5000. The thickness of the gallium nitride layer is 200~3000nm.

4. The method according to claim 3, characterized in that, The number of gallium nitride layers is 1 to 3.

5. The method according to claim 1, characterized in that, The substrate is further cleaned and dried before magnetron sputtering.

6. The method according to claim 5, characterized in that, The cleaning process includes ultrasonic cleaning, using acetone or anhydrous ethanol as the solvent, with an ultrasonic time of 5-10 minutes, an ultrasonic power of 80-90W, and 2-3 ultrasonic cleaning cycles.

7. The method according to claim 5, characterized in that, Drying is done by blowing with nitrogen gas.

8. The method according to any one of claims 5 to 7, characterized in that, The substrate is a silicon-based substrate.

9. A gallium nitride semiconductor material, characterized in that, The substrate, prepared by the method according to any one of claims 1 to 8, comprises a substrate and an aluminum nitride buffer layer, an aluminum nitride layer, and a gallium nitride layer sequentially formed on the surface of the substrate.

10. The application of the method as described in any one of claims 1 to 8 in the preparation of semiconductor materials.

Images