Method for epitaxial growth of gallium antimonide film crystal on surface of gallium arsenide

Abstract

The invention discloses a method for epitaxial growth of a gallium antimonide film crystal on the surface of gallium arsenide, and belongs to the technical field of synthesis of compound semiconductor materials. The method comprises the following steps: step 1, placing a gallium arsenide substrate wafer on a bracket in a crystal reaction furnace, and vacuumizing the crystal reaction furnace; 2, conveying argon to a crystal reaction furnace, and replacing air; step 3, conveying antimonane to a crystal reaction furnace, and driving argon in a furnace body with antimonane steam; 4, trimethyl gallium is conveyed to a crystal reaction furnace; step 5, heating the crystal reaction furnace to 480-500 DEG C, and reacting for 0.5-3 hours at the temperature of 480-500 DEG C; then raising the temperature to 850 to 870 DEG C, and reacting for 1 to 1.5 hours at the temperature; and step 6, gradually reducing the temperature of the crystal reaction furnace to room temperature, and taking out a product to obtain an epitaxial gallium antimonide thin film crystal finished product. According to the invention, the gallium antimonide crystal epitaxial layer with uniform thickness and good quality can be obtained on the gallium arsenide substrate at a low temperature in a short time.

Description

Technical Field

[0001] This invention relates to the field of compound semiconductor material synthesis technology, and in particular to a method for epitaxial gallium antimonide thin film crystals on the surface of gallium arsenide. Background Technology

[0002] Gallium antimonide (GaSb) is a group III-V compound semiconductor material with a direct bandgap of 0.725 eV (300 K), a lattice constant of 0.60959 nm, and a zincblende crystal structure. GaSb not only possesses a wide range of variable band gaps and band differences but also exhibits high electron mobility, making it ideal for the fabrication of high-speed, low-power electronic devices and mid-infrared devices.

[0003] Gallium antimonide is often grown as an epitaxial thin film on substrates such as gallium arsenide, indium phosphide, and indium arsenide. Among them, gallium arsenide (GaAs) substrates are needed for many applications due to their semi-insulating, large area, favorable thermal properties, excellent n-type and p-type ohmic contacts, low cost and high quality, and also provide the possibility of monolithic integration for optoelectronic devices.

[0004] The traditional method for forming gallium antimonide epitaxy is physical vapor deposition (PVD), which involves mixing high-purity antimony and high-purity gallium in a specific ratio and then sublimating and depositing the mixture in a vacuum high-temperature quartz boat to obtain gallium antimonide crystals. This method requires reaction temperatures as high as 1500℃, consumes a lot of energy, and the high-purity antimony and gallium are highly susceptible to incomplete reaction due to sublimation. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for epitaxially growing gallium antimonide thin film crystals on a gallium arsenide surface. This method utilizes the metathesis reaction of antimonide and trimethylgallium to form gallium antimonide epitaxial thin film wafers on a gallium arsenide substrate.

[0006] The technical solution adopted in this invention is: A method for epitaxial gallium antimonide thin film crystals on the surface of gallium arsenide, which employs a gallium antimonide crystal material preparation apparatus, the apparatus including a crystal reactor, an antimonane storage tank, a trimethylgallium storage tank and an argon gas storage tank; the interior of the crystal reactor is provided with a support for placing the substrate, and the exterior of the crystal reactor is provided with a heating device; The antimonyane storage tank is connected to the crystal reactor via an antimonyane vapor delivery pipeline; the trimethylgallium storage tank is connected to the crystal reactor via a trimethylgallium vapor delivery pipeline; the argon storage tank is connected to a buffer tank via an argon delivery pipeline, and the buffer tank is connected to the crystal reactor via a buffer pipeline; the crystal reactor is also connected to a vacuum pipeline; the method includes the following steps: Step 1: Place the gallium arsenide substrate wafer on a support inside the crystal reactor and evacuate the crystal reactor through a vacuum pipe. Step 2: Argon gas from the argon storage tank is transferred to the crystal reactor via a buffer tank to completely replace the air in the crystal reactor with argon gas; Step 3: The antimonyane in the antimonyane storage tank is transported to the crystal reaction furnace through the antimonyane vapor pipeline, and the antimonyane vapor is used to drive out the argon gas in the furnace body; Step 4: The trimethylgallium in the trimethylgallium storage tank is transported to the crystal reactor via a trimethylgallium vapor pipeline; Step 5: Heat the crystal reactor to 480-500℃ using a heating device and react at this temperature for 0.5-3 hours; then heat the crystal reactor to 850-870℃ and react at this temperature for 1-1.5 hours. Step 6: Gradually lower the temperature of the crystal reactor to room temperature, remove the product, and obtain the finished epitaxial gallium antimonide thin film crystal.

[0007] The beneficial technical effects of the present invention are as follows: This invention uses antimonyane and trimethylgallium as precursors to synthesize gallium antimonide epitaxial wafers. From a process perspective, both antimonyane and trimethylgallium are gaseous, significantly improving the contact area and reaction efficiency. Furthermore, the gallium antimonide thin film generated using this method can more uniformly cover the gallium arsenide substrate. From an energy consumption perspective, the maximum required reaction temperature is only 850℃, far lower than the 1500℃ of traditional methods, which also has positive implications for energy saving and consumption reduction. Through this method, a gallium antimonide crystal epitaxial layer of uniform thickness and good quality can be obtained on a gallium arsenide substrate at a lower temperature and in a shorter time. Attached Figure Description

[0008] Figure 1 This is a flowchart of the method for epitaxial gallium antimonide thin film crystal on the surface of gallium arsenide according to the present invention; Figure 2 This is a schematic diagram illustrating the structural principle of one embodiment of the gallium antimonide crystal material preparation apparatus used in this invention. Figure 3 A schematic diagram of the structure and principle of the crystal reactor in a gallium antimonide crystal material preparation device; Figure 4 A schematic diagram illustrating the structural principle of the antimonane storage tank in a gallium antimonide crystal material preparation device; Figure 5 This is a schematic diagram of the structural principle of another embodiment of the gallium antimonide crystal material preparation device used in this invention; Figure 6 The image shows the morphology of the GaSb / GaAs epitaxial layer obtained in an embodiment of the present invention. Figure 7 EDS image of the gallium antimonide crystal epitaxial layer obtained in an embodiment of the present invention; Figure 8The XRD-2θ scan pattern of the GaSb / GaAs epitaxial layer obtained in the embodiments of the present invention; Figure 9 The images show the Raman spectra of the GaSb thin film and the GaAs substrate; where (a) is a 30 μm GaSb thin film and (b) is a gallium arsenide substrate.

[0009] In the diagram: 1-Crystal reactor, 2-Antimonane storage tank, 3-Trimethylgallium storage tank, 4-Argon storage tank, 5-Substrate, 6-Support, 7-Heating device, 8-Antimonane vapor delivery pipeline, 9-Trimethylgallium vapor delivery pipeline, 10-Argon delivery pipeline, 11-Buffer tank, 12-Buffer pipeline, 13-First control valve, 14-Second control valve, 15-Vacuum pumping pipeline, 16-Vacuum pump, 17-Insulation layer, 18-Exhaust pipeline, 19-Waste gas collection tank, 20-Seventh control valve; 201-First outlet conduit, 202-First heating coil, 203-Third control valve; 301-Second outlet conduit, 302-Second heating coil, 303-Fourth control valve; 401-Main carrier pipe, 402-First carrier branch pipe, 403-Second carrier branch pipe, 404-Fifth control valve, 405-Sixth control valve; 601-Vertical support rod, 602-Horizontal support seat. Detailed Implementation

[0010] This invention discloses a method for epitaxially growing gallium antimonide thin film crystals on gallium arsenide (GaAs) surfaces. The method utilizes antimonide and trimethylgallium to generate GaAs epitaxial thin film crystals on the GaAs surface. First, a GaAs wafer substrate is placed in a reaction chamber. The chamber is evacuated and high-purity argon gas is introduced to purge and replace the gas inside, ensuring the absence of nitrogen and oxygen. Then, high-purity antimonide vapor and high-purity trimethylgallium vapor are introduced from the top and bottom of the reaction chamber, respectively, using argon as a carrier. After sufficient contact between the two vapors, the reaction chamber is heated to 850°C, and the pressure inside the chamber is maintained. Under this temperature and pressure, GaAs thin film crystals are generated on the GaAs substrate surface. This method allows for the generation of a uniform and high-quality GaAs epitaxial layer on a GaAs substrate in a relatively short time.

[0011] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0012] A method for epitaxially growing gallium antimonide thin film crystals on the surface of gallium arsenide, using a gallium antimonide crystal material preparation apparatus, such as... Figures 2-4As shown, the device includes a crystal reactor 1, an antimony storage tank 2, a trimethylgallium storage tank 3, and an argon storage tank 4. The crystal reactor 1 includes a furnace body, with a support 6 for placing a substrate 5 inside the furnace body and a heating device 7 on the outside of the furnace body. The antimony storage tank 2 is connected to the furnace body via an antimony vapor delivery pipe 8. The trimethylgallium storage tank 3 is connected to the furnace body via a trimethylgallium vapor delivery pipe 9. The argon storage tank 4 is connected to a buffer tank 11 via an argon delivery pipe 10, and the buffer tank 11 is connected to the furnace body via a buffer pipe 12. A first control valve 13 is installed on the argon delivery pipe 10, and a second control valve 14 is installed on the buffer pipe 12. The furnace body is also connected to a vacuum pipe 15. The vacuum pipe 15 is connected to a vacuum pump 16.

[0013] like Figure 2 As shown, the furnace body is arranged horizontally, with the support 6 installed at the center of the furnace body. The support 6 includes a vertical support rod 601, the bottom end of which is connected to the inner wall of the bottom of the furnace body, and the top end of which is connected to a horizontal support base 602, which is circular. A circular substrate is placed on the horizontal support base 602.

[0014] The aforementioned heating device uses a heating wire, which is wound around the outer perimeter of the furnace body. An insulation layer 17 is also provided on the outer side of the furnace body, with the heating wire positioned between the furnace body and the insulation layer. Alternatively, a cavity heater or similar device can be used, with the crystal reaction furnace placed within the cavity heater.

[0015] like Figure 3 As shown, the antimonyane storage tank 2 is connected to a first outlet conduit 201, and a first heating coil 202 is installed at the first outlet conduit 201. The first outlet conduit 201 is connected to the furnace body through an antimonyane vapor delivery pipe 8, and a third control valve 203 is installed on the antimonyane vapor delivery pipe. The trimethylgallium storage tank 3 is connected to a second outlet conduit 301, and a second heating coil 302 is installed at the second outlet conduit 301. The second outlet conduit 301 is connected to the furnace body through a trimethylgallium vapor delivery pipe 9, and a fourth control valve 303 is installed on the trimethylgallium vapor delivery pipe 9.

[0016] The buffer tank 11 is designed to release pressure to the buffer tank 11 when the pressure in the crystal reactor is too high, and to replenish gas to the crystal reactor through the buffer tank 11 when the pressure is lower than the set value, so that the overall reaction is stable and controllable.

[0017] As a further design of the above-mentioned device, such as Figure 4As shown, the argon storage tank 4 is also connected to a first carrier branch pipe 402 and a second carrier branch pipe 403 via a main carrier pipe 401. The first carrier branch pipe 402 is connected to an antimonyane vapor delivery pipe 8, and the second carrier branch pipe 403 is connected to a trimethylgallium vapor delivery pipe 9. A fifth control valve 404 is installed on the first carrier branch pipe 402, and a sixth control valve 405 is installed on the second carrier branch pipe 403. With the above structure, high-purity antimonyane vapor and high-purity trimethylgallium vapor can be introduced into the crystal reactor using argon as a carrier.

[0018] An exhaust port is also provided on the furnace body, which is connected to a waste gas collection tank 19 via an exhaust pipe 18. A seventh control valve 20 is installed on the exhaust pipe 18. After the reaction is completed, the remaining gas can be discharged through the exhaust pipe and collected in the waste gas collection tank 19.

[0019] like Figure 1 As shown, the method includes the following steps: Step 1: Place the gallium arsenide substrate wafer on the support 6 at the center of the crystal reactor 1. Evacuate the crystal reactor through the vacuum pipe 15 until the vacuum level inside the crystal reactor reaches 10. -2 Pa, stop vacuuming.

[0020] Step 2: Argon gas from argon storage tank 4 is transferred to crystal reactor 1 via buffer tank 11 to completely replace the air in crystal reactor 1 with argon gas. Specifically, argon gas is continuously introduced at a rate of 10-15 L / min until the internal pressure of the crystal reactor reaches 0.12-0.15 MPa.

[0021] Step 3: The antimonyane in the antimonyane storage tank 2 is transported to the crystal reactor 1 via the antimonyane vapor delivery pipe 8, using the antimonyane vapor to drive out the argon gas in the furnace. Specifically, the outlet of the antimonyane storage tank is heated to 35-40°C by the first heating coil, so that the antimonyane vapor enters the crystal reactor 1 at a rate of 10-15 L / min, and the flow is stopped after 2-5 minutes, maintaining the pressure inside the crystal reactor at 0.12-0.15 MPa.

[0022] Step 4: The trimethylgallium in the trimethylgallium storage tank 3 is transported to the crystal reactor 1 via the trimethylgallium vapor transport pipe 9. Specifically, the outlet of the trimethylgallium storage tank is heated to 90-100°C by the second heating coil, so that the trimethylgallium vapor enters the crystal reactor 1 at a rate of 10-15 L / min. After 3-7 minutes, the gas supply is stopped, and the pressure inside the crystal reactor 1 is maintained at 0.2-0.25 MPa.

[0023] Step 5: Heat the crystal reactor 1 to 480-500℃ using heating device 7, and react at this temperature for 0.5-3 hours; then further heat the crystal reactor to 850-870℃, and react at this temperature for 1-1.5 hours. Monitor the pressure inside the crystal reactor in real time during the reaction. Once the pressure inside the crystal reactor remains constant at 0.3 MPa, continue heating the crystal reactor to 850-870℃ and continue the reaction until the pressure inside the crystal reactor remains constant at 0.37 MPa.

[0024] Step 6: Gradually reduce the temperature of the crystal reactor to room temperature at a rate of 5-10℃ / min, remove the product, and obtain an epitaxial gallium antimonide thin film crystal product with a thickness of 28-32μm.

[0025] Of course, steps three and four above can also be adopted. Figure 4 The apparatus shown is used to transport antimony vapor and trimethylgallium vapor to crystal reactor 1 via argon gas for reaction.

[0026] The present invention will be further described below with reference to specific embodiments.

[0027] A method for epitaxial gallium antimonide thin film crystals on gallium arsenide surface utilizes the metathesis reaction of antimonyane (hydrogen antimonide, chemical formula SbH3, melting point: -88℃, boiling point: -18.4℃) and trimethylgallium (melting point -15.8℃, boiling point 55.8℃, abbreviation TMG) ​​to form gallium antimonide epitaxial thin film wafers on gallium arsenide substrate. The process is as follows: Step 1: Place a 6-inch diameter gallium arsenide substrate wafer into the source region of the crystal reactor's reaction chamber. Evacuate the crystal reactor for 15 minutes until the vacuum level reaches 10. -2 Pa, stop vacuuming.

[0028] Step 2: Continuously introduce high-purity argon gas at a rate of 15 L / min for 15 minutes to completely replace the residual air in the crystal reactor; maintain the system pressure at 0.12 MPa.

[0029] Step 3: Heat the outlet of the antimonyane storage tank to 40°C, and let the antimonyane vapor enter the crystal reactor at a rate of 15L / min. At the same time, use the antimonyane vapor to drive out the argon gas in the reaction chamber. The driven argon gas can be returned to the buffer tank or discharged to the waste gas collection tank. Stop the flow after 2 minutes; maintain the system pressure at 0.12MPa.

[0030] Step 4: Heat the outlet of the trimethylgallium storage tank to 100°C, and let the trimethylgallium vapor enter the crystal reactor at a rate of 15L / min. After 4.5 minutes, stop the gas supply and maintain the system pressure at 0.25Mpa.

[0031] Step 5: Heat the reaction chamber to 780°C at a rate of 20°C / min and maintain this temperature for 30 minutes.

[0032] Step Six: After the system has been reacting for 1.5 hours, observe that the system pressure remains constant at 0.3 MPa. Then, heat the crystal reactor to 850°C and continue the reaction. After about 1.2 hours, the system pressure remains constant at 0.37 MPa.

[0033] Step 7: Gradually reduce the system temperature to room temperature at a rate of 10℃ / min, remove the product, and obtain an epitaxial gallium antimonide thin film wafer with a thickness of 30μm.

[0034] This invention utilizes the reaction of antimonyane and trimethylgallium at high temperature (SbH3+TMG=GaSb↓+3CH4). From a process perspective, this reaction process is clean and efficient, forming a uniform gallium antimony deposition film on the surface of a gallium arsenide substrate.

[0035] Figure 6 The image shows the morphology of the GaSb / GaAs epitaxial layer obtained in an embodiment of the present invention; it can be seen from the image that gallium antimonide is uniformly covered on the surface of the gallium arsenide substrate. Figure 7 The image shows the EDS diagram of the gallium antimonide crystal epitaxial layer obtained in the embodiment of the present invention; it can be seen from the figure that the antimony to gallium ratio is stable at 1:1. Figure 8 The XRD-2θ scan pattern of the GaSb / GaAs epitaxial layer prepared in the embodiment of the present invention is shown. The 2θ scan results show the diffraction peak positions of GaSb (114) and (112) crystal plane clusters. In addition, there are only diffraction peaks of the GaAs substrate and no other impurity peaks appear, which indicates that the crystal orientation of the GaSb epitaxial layer is good. Figure 9 The images show the Raman spectra of the GaSb thin film and the GaAs substrate; (a) is a 30 μm GaSb thin film, and (b) is a gallium arsenide substrate. The Raman spectra show that the gallium arsenide substrate and the gallium antimonide epitaxial layer are highly compatible.

[0036] For any parts not mentioned above, existing technologies can be adopted or referenced.

[0037] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for epitaxially growing gallium antimonide thin film crystals on the surface of gallium arsenide, characterized in that, A gallium antimonide crystal material preparation apparatus is used, which includes a crystal reactor, an antimony storage tank, a trimethylgallium storage tank, and an argon gas storage tank; the interior of the crystal reactor is equipped with a support for placing the substrate, and the exterior of the crystal reactor is equipped with a heating device; The antimonyane storage tank is connected to the crystal reactor via an antimonyane vapor delivery pipeline; the trimethylgallium storage tank is connected to the crystal reactor via a trimethylgallium vapor delivery pipeline; the argon storage tank is connected to a buffer tank via an argon delivery pipeline, and the buffer tank is connected to the crystal reactor via a buffer pipeline; the crystal reactor is also connected to a vacuum pipeline; the method includes the following steps: Step 1: Place the gallium arsenide substrate wafer on a support inside the crystal reactor and evacuate the crystal reactor through a vacuum pipe. Step 2: Argon gas from the argon storage tank is transported to the crystal reactor via a buffer tank to completely replace the air in the crystal reactor with argon gas; Step 3: The antimonyane in the antimonyane storage tank is transported to the crystal reaction furnace through the antimonyane vapor pipeline, and the antimonyane vapor is used to drive out the argon gas in the furnace body; Step 4: The trimethylgallium in the trimethylgallium storage tank is transported to the crystal reactor via a trimethylgallium vapor pipeline; Step 5: Heat the crystal reactor to 480-500℃ using a heating device and react at this temperature for 0.5-3 hours; then heat the crystal reactor to 850-870℃ and react at this temperature for 1-1.5 hours. Step 6: Gradually lower the temperature of the crystal reactor to room temperature, remove the product, and obtain the finished epitaxial gallium antimonide thin film crystal.

2. The method for epitaxially growing gallium antimonide thin film crystal on the surface of gallium arsenide according to claim 1, characterized in that: The support frame is positioned at the center of the crystal reactor; in step one, the crystal reactor is evacuated through a vacuum pipe until the vacuum level inside the crystal reactor reaches 10. -2 Pa, stop vacuuming.

3. The method for epitaxially growing gallium antimonide thin film crystal on the surface of gallium arsenide according to claim 1, characterized in that: In step two, argon gas is continuously introduced at a rate of 10-15 L / min until the internal pressure of the crystal reactor reaches 0.12-0.15 MPa.

4. The method for epitaxially growing gallium antimonide thin film crystal on the surface of gallium arsenide according to claim 1, characterized in that: A first outlet conduit is connected to the antimonyane storage tank, and a first heating coil is installed at the first outlet conduit. In step three, the outlet of the antimonyane storage tank is heated to 35-40°C by the first heating coil, so that antimonyane vapor enters the crystal reactor at a rate of 10-15 L / min. After 2-5 minutes, the flow is stopped, and the pressure inside the crystal reactor is maintained at 0.12-0.15 MPa.

5. The method for epitaxially growing gallium antimonide thin film crystal on the surface of gallium arsenide according to claim 1, characterized in that: A second outlet conduit is connected to the trimethylgallium storage tank, and a second heating coil is installed at the second outlet conduit. In step four, the outlet of the trimethylgallium storage tank is heated to 90-100°C by the second heating coil, so that the trimethylgallium vapor enters the crystal reactor at a rate of 10-15 L / min. After 3-7 minutes, the gas supply is stopped, and the pressure inside the crystal reactor is maintained at 0.2-0.25 MPa.

6. The method for epitaxially growing gallium antimonide thin film crystal on the surface of gallium arsenide according to claim 1, characterized in that: In step five, the pressure inside the crystal reactor is monitored in real time during the reaction. Once the pressure inside the crystal reactor remains constant at 0.3 MPa, the crystal reactor is heated to 850-870°C and the reaction continues until the pressure inside the crystal reactor remains constant at 0.37 MPa.

7. The method for epitaxially growing gallium antimonide thin film crystal on the surface of gallium arsenide according to claim 1, characterized in that: In step six, the temperature inside the crystal reactor is gradually reduced to room temperature at a rate of 5-10℃ / min; the thickness of the obtained gallium antimonide thin film crystal is 28-32μm.

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