An epitaxial growth apparatus for gallium oxide, an ultrawide bandgap semiconductor material

Abstract

This invention discloses an epitaxial growth apparatus for gallium oxide (GaO), an ultra-wide bandgap semiconductor material. The apparatus includes a heating shell with an outlet. Inside the shell are a gallium chloride (GaC) channel structure, an oxygen channel structure, and a growth disk. The GaC channel structure comprises an inlet pipe, a gallium boat, a first gas-leveling baffle, and a spray pipe connected in sequence. The oxygen channel structure includes an oxygen inlet pipe and a second gas-leveling baffle, with the front end of the oxygen inlet pipe extending outside the shell. The growth disk is a rotatable disk with its upper surface horizontally positioned. The substrate to be grown is placed on the upper surface of the growth disk. A driving structure is located inside the growth disk, driving the disk to rotate. The lower end of the spray pipe and the rear end of the second gas-leveling baffle are both directly opposite the upper surface of the growth disk. An outlet is provided on the shell. This invention proposes a dedicated HVPE (High-Voltage Gas Surface Evaporation) device for six-inch GaO epitaxial wafers. Through simulation optimization, the corresponding gas mixing and homogenization structures were optimized. This structure and process can significantly improve the uniformity of GaO deposition.

Description

Technical Field

[0001] This invention relates to the technical field of gallium oxide growth, and more particularly to an epitaxial growth apparatus for gallium oxide, an ultrawide bandgap semiconductor material. Background Technology

[0002] Gallium oxide (Ga2O3) is an ultra-wide bandgap oxide semiconductor material, representing the third generation of semiconductor materials after SiC and GaN. Ga2O3 possesses excellent optoelectronic properties, good thermal stability, and chemical stability. β-Ga2O3 films, in particular, exhibit high transparency in the deep ultraviolet region, making them ideal for fabricating ultraviolet optoelectronic materials. The breakdown field strength of β-Ga2O3 is 8 MV / cm, significantly higher than that of SiC and GaN, indicating its great potential in field-effect transistors, Schottky diodes, and other power electronic devices. Furthermore, Ga2O3 exhibits excellent gas-sensing properties, making it a candidate material for fabricating high-temperature oxygen-sensitive devices. Therefore, Ga2O3 has become a hot research topic.

[0003] HVPE is short for hydride vapor phase epitaxy. HVPE crystals grow rapidly; in reports of GaN growth using HVPE, GaN thin films have grown at speeds exceeding 100 μm / h. Simultaneously, the HVPE system has low manufacturing costs and relatively simple equipment processes, enabling the growth of high-quality thick films while maintaining high growth rates, thus attracting considerable attention from researchers in recent years. The HVPE system for growing β-Ga2O3 thin films mainly consists of four parts: (1) a furnace and reactor; (2) a gallium boat and gas supply pipes; (3) a gas preparation system; and (4) a tail gas treatment system.

[0004] The reaction process for growing β-Ga2O3 thin films by HVPE involves the following steps:

[0005] In the first step, a carrier gas carrying HCl gas is introduced into the gallium boat, where it reacts with the metallic gallium to generate GaCl gas. Simultaneously, a carrier gas carrying O2 is introduced into the reaction chamber, and a separating gas N2 is introduced between the O2 and the GaCl inlet.

[0006] In the second step, the carrier gas continues to carry GaCl gas to the top of the substrate to react with O2, generating β-Ga2O3 which is then deposited on the substrate.

[0007] The third step involves the carrier gas carrying the exhaust gas into the exhaust gas treatment system.

[0008] In practice, it has been found that the film thickness on the substrate is not uniform when growing β-Ga2O3 films using existing HVPE methods. The reasons are as follows:

[0009] 1. Both the GaCl and O2 pipes that blow gas onto the substrate are circular. This type of pipe has a concentrated gas outlet and a fast flow rate, which results in a short residence time for the two gas components above the substrate. There is not enough time for substrate deposition, which leads to a large consumption of raw materials. At the same time, the pipe diameter is significantly smaller than the substrate width, and the blowing can only be concentrated in a small part of the center of the substrate. The gas concentration around the substrate is low, resulting in uneven substrate deposition.

[0010] 2. When GaCl and O2 converge on the substrate surface, they will generate impacts, which will form vortices and make the gas flow on the substrate surface complex and unpredictable, resulting in uneven substrate deposition. Summary of the Invention

[0011] To address the two technical problems mentioned in the background art that lead to uneven substrate deposition, this invention provides an epitaxial growth apparatus for gallium oxide, an ultrawide bandgap semiconductor material.

[0012] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0013] An epitaxial growth apparatus for gallium oxide, an ultrawide bandgap semiconductor material, includes: a housing with an outlet; a gallium chloride channel structure, an oxygen channel structure, and a growth disk within the housing; and an inert gas filling the housing. The gallium chloride channel structure includes an inlet pipe, a gallium boat, a first gas-leveling baffle, and a spraying pipe connected in sequence. The inlet pipe extends beyond the housing, allowing hydrogen chloride gas to pass through. The gallium boat is a storage chamber containing gallium, where hydrogen chloride gas reacts with gallium to generate gallium chloride. The gallium chloride gas enters the front end of the first gas-leveling baffle, which is a hollow plate with a width matching the diameter of the substrate to be grown and bent along its length. The rear end of the first gas-leveling baffle is connected to the upper end of the spraying pipe. After passing through the inner cavity of the first gas-leveling baffle... The oxygen is sprayed from the spray pipe, the width of which matches the diameter of the substrate to be grown. The oxygen channel structure includes an oxygen inlet pipe and a second gas equalization baffle. The front end of the oxygen inlet pipe extends outside the shell, and the inert gas mixed with oxygen can enter the front end of the second gas equalization baffle through the oxygen inlet pipe. The second gas equalization baffle is a hollow plate with a width matching the diameter of the substrate to be grown and a bend in the length direction. The rear end of the second gas equalization baffle is an open end, and the inert gas mixed with oxygen can be sprayed out from the rear end of the second gas equalization baffle. The growth disk is a rotatable disk with a horizontally set upper surface. The substrate to be grown is placed on the upper surface of the growth disk. A driving structure is set inside the growth disk, and the driving structure drives the growth disk to rotate. The lower end of the spray pipe and the rear end of the second gas equalization baffle are both directly facing the upper surface of the growth disk. An air outlet is set on the shell.

[0014] In some of these embodiments, both the first and second air-bearing baffles are serpentine bends.

[0015] In some embodiments, there are several spray nozzles, which are arranged in parallel at equal intervals along the front-to-back direction.

[0016] In some of these embodiments, the spray nozzle is tilted, with the angle between the spray nozzle and the horizontal plane being 10°-30°.

[0017] In some embodiments, a separation plate is provided on the upper surface of the growth disk, and the separation plate is arranged parallel to the upper surface of the growth disk. The distance between the separation plate and the growth disk is no more than 0.5 cm. The lower end of the spray pipe and the rear end of the second gas flow baffle both extend into the position between the separation plate and the growth disk. The air blowing from the lower end of the spray pipe and the rear end of the second gas flow baffle towards the surface of the growth disk in the horizontal direction is from front to back. The separation plate is used to reduce the height of the space above the growth disk, so that when the gallium chloride gas and the inert gas mixed with oxygen collide with each other on the surface of the growth disk, they cannot flow back and form a vortex.

[0018] In some embodiments, the housing is provided with a reaction source region and an epitaxial layer growth region. The rear end of the reaction source region is connected to the front end of the epitaxial layer growth region through an insulating and sealing partition. A first heating structure is provided outside the reaction source region, and a second heating structure is provided outside the epitaxial layer growth region. The inlet pipe, the gallium boat, and the front half of the first gas-uniforming baffle are all located in the reaction source region. The rear half of the first gas-uniforming baffle and the spray pipe are located in the epitaxial layer growth region. The oxygen inlet pipe and the front half of the second gas-uniforming baffle are both located in the reaction source region, and the rear half of the second gas-uniforming baffle is located in the epitaxial layer growth region. The first heating structure and the second heating structure can heat the reaction source region and the epitaxial layer growth region respectively, so that the heating temperature of the reaction source region and the epitaxial layer growth region meets the preset temperature requirements.

[0019] In some of these embodiments, the temperature of the reaction source region is higher than that of the epitaxial layer growth region.

[0020] In some of these embodiments, the upper surface of the growth disk is a quartz surface.

[0021] In some of these embodiments, the inert gas mixed with oxygen is argon or nitrogen.

[0022] In some embodiments, the drive structure inside the growth disc is a rotary motor, which drives the growth disc to rotate.

[0023] The advantages of this invention are as follows:

[0024] 1. The present invention rectifyes the airflow to be sprayed onto the substrate by setting a first gas-uniform baffle and a second gas-uniform baffle. The airflow, which was originally in a circular pipe, is transformed into a shape with a width adapted to the width of the substrate by passing through the inner cavity of the baffle. At the same time, since the width of the baffle is significantly larger than the diameter of the inlet pipe and the oxygen inlet pipe, the gas velocity is significantly reduced. This results in a slower flow rate when the final airflow is sprayed onto the substrate, while also covering the entire substrate well, which greatly improves the uniformity of deposition.

[0025] 2. The present invention provides a separation plate on the upper surface of the growth disk, replacing the traditional N2 protective layer. The separation plate is used to reduce the height of the space above the growth disk, so that when gallium chloride gas and inert gas mixed with oxygen collide with each other on the surface of the growth disk, they cannot flow back and thus cannot form vortices, thereby improving the uniformity of deposition. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view of the horizontal gallium oxide growth apparatus of the present invention;

[0027] Figure 2 This is an exploded view of the horizontal gallium oxide growth apparatus of the present invention;

[0028] Figure 3 This is a perspective view of the gallium chloride channel structure of the horizontal gallium oxide growth apparatus of the present invention;

[0029] Figure 4 This is a schematic diagram showing the gas flowing smoothly across the upper surface of the growth plate under the action of the separation plate.

[0030] The labels in the figure are as follows: shell 1, reaction source region 1a, epitaxial layer growth region 1b, first heating structure 11, second heating structure 12, insulating and sealing partition 13, gallium chloride channel structure 2, gas inlet pipe 21, gallium boat 22, first gas flow baffle 23, spray pipe 24, oxygen channel structure 3, oxygen inlet pipe 31, second gas flow baffle 32, growth disk 4, separation plate 5. Detailed Implementation

[0031] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0032] It should be noted that the terms such as "upper", "lower", "left", "right", "front", and "back" used in the invention are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0033] like Figure 1-3 As shown,

[0034] The horizontal gallium oxide growth apparatus of the present invention includes a gallium chloride channel structure 2 that introduces HCl gas and has a spraying function. The gallium chloride channel structure 2 includes an inlet pipe 21, through which HCl gas is introduced into a gallium boat 22 containing Ga, and then the gas that has reacted into gallium chloride GaCl is sprayed out from the spray pipe 24 after passing through a first gas equalization baffle 23.

[0035] The first air-baffle plate 23 has a size of 100-200mm, and the angle between the first air-baffle plate 23 and the horizontal plane is 10°-30°.

[0036] Ar or N2 carries O2 into the oxygen inlet pipe 31, then into the second gas-uniforming baffle 32, and finally exits from the end of the second gas-uniforming baffle 32.

[0037] GaCl and O2 react on the substrate to form a Ga2O3 thin film.

[0038] The reaction equation inside gallium boat 22 is as follows:

[0039]

[0040] The reaction equation on the substrate surface is:

[0041]

[0042] Finally, the excess gas is discharged from the outlet.

[0043] The housing 1 is provided with a reaction source region 1a and an epitaxial layer growth region 1b. The rear end of the reaction source region 1a is connected to the front end of the epitaxial layer growth region 1b through an insulating and sealing partition 13. A first heating structure 11 is provided outside the reaction source region 1a, and a second heating structure 12 is provided outside the epitaxial layer growth region 1b. The inlet pipe 21, the gallium boat 22, and the front half of the first gas-uniforming baffle 23 are all located in the reaction source region 1a. The rear half of the first gas-uniforming baffle 23 and the spray pipe 24 are located in the epitaxial layer growth region 1b. The oxygen inlet pipe 31 and the front half of the second gas-uniforming baffle 32 are both located in the reaction source region 1a, and the rear half of the second gas-uniforming baffle 32 is located in the epitaxial layer growth region 1b. The heating temperature of the reaction source region 1a is 1123K, and the temperature of the epitaxial layer growth region 1b is 1323K.

[0044] A separation plate 5 is provided on the upper surface of the growth disk 4. The separation plate 5 is parallel to the upper surface of the growth disk 4, and the distance between the separation plate 5 and the growth disk 4 is no more than 0.5 cm. The lower end of the spray pipe 24 and the rear end of the second air-level baffle 32 both extend into the space between the separation plate 5 and the growth disk 4. The horizontal air blowing from the lower end of the spray pipe 24 and the rear end of the second air-level baffle 32 towards the surface of the growth disk 4 is from front to back. The separation plate 5 is used to reduce the height of the space above the growth disk 4. Figure 4As can be seen, the gas will grow in the reaction zone after entering below the separation plate 5. The flow velocity in the flow zone is relatively stable, without eddies, which improves the uniformity of deposition. The growth disk 4, by rotating, allows the substrate to contact the gas more uniformly, further improving the uniformity of deposition.

[0045] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. An epitaxial growth apparatus for gallium oxide, an ultrawide bandgap semiconductor material, characterized in that: The utility model provides a gallium arsenide epitaxial wafer growth device, including shell (1), the shell (1) is provided with the air outlet, the shell (1) is provided with gallium chloride channel structure (2), oxygen channel structure (3) and growth tray (4) inside, the shell (1) is filled with inert gas, the gallium chloride channel structure (2) includes the gas inlet pipe (21) that communicates in turn, gallium boat (22), first uniform gas baffle (23) and spray pipe (24), the gas inlet pipe (21) front end stretches to the shell (1) outside, and hydrogen chloride gas can be passed into the gas inlet pipe (21), the gallium boat (22) is the storage compartment that is equipped with gallium inside, and the hydrogen chloride gas is reacted with gallium in the gallium boat (22) and generates gallium arsenide, and the gallium arsenide gas enters the first uniform gas baffle (23) front end, and the first uniform gas baffle (23) is hollow board with the diameter of the substrate to be grown width and length direction has the bending of matching, the first uniform gas baffle (23) rear end with spray pipe (24) upper end communicates, and the gallium arsenide gas is sprayed from spray pipe (24) after the inner chamber of first uniform gas baffle (23), the width of spray pipe (24) matches the diameter of the substrate to be grown, and the oxygen channel structure (3) includes oxygen inlet pipe (31) and second uniform gas baffle (32), and the oxygen inlet pipe (31) front end stretches to the shell (1) outside, and the inert gas mixed with oxygen can pass through the oxygen inlet pipe (31) and enter the second uniform gas baffle (32) front end, and the second uniform gas baffle (32) is hollow board with the diameter of the substrate to be grown width and length direction has the bending of matching, and the second uniform gas baffle (32) rear end is open end, and the inert gas mixed with oxygen can be sprayed from the second uniform gas baffle (32) rear end, and the growth tray (4) is rotatable tray, and the growth tray (4) upper surface is horizontally arranged, and the substrate to be grown is placed on the growth tray (4) upper surface, and the growth tray (4) is provided with drive structure inside, and the drive structure drives the growth tray (4) rotation, and the lower end of spray pipe (24) and the rear end of second uniform gas baffle (32) are all opposite to the growth tray (4) upper surface, and the first uniform gas baffle (23) and the second uniform gas baffle (32) are all serpentine bending, and the growth tray (4) upper surface is provided with separation plate (5), and the separation plate (5) is parallelly arranged with the growth tray (4) upper surface, and the interval between separation plate (5) and the growth tray (4) is no more than 0.5cm, and the lower end of spray pipe (24) and the rear end of second uniform gas baffle (32) are all stretched into the position between separation plate (5) and the growth tray (4), and the lower end of spray pipe (24) and the rear end of second uniform gas baffle (32) are all from front to back to the horizontal direction of the growth tray (4) surface blowing, and the separation plate (5) is used for reducing the height of the space above the growth tray (4), so that the inert gas mixed with oxygen and gallium arsenide gas can not backflow when colliding on the growth tray (4) surface, forms vortex, and the spray pipe (24) is obliquely arranged.

2. The epitaxial growth apparatus of claim 1, wherein the apparatus is characterized by: The number of the spraying pipes (24) is several, and the spraying pipes (24) are arranged in parallel at equal intervals along the front-rear direction.

3. The epitaxial growth apparatus of claim 2, wherein the apparatus is characterized by: The shell (1) is provided with a reaction source area (1a) and an epitaxial layer growth area (1b), the rear end of the reaction source area (1a) is connected to the front end of the epitaxial layer growth area (1b) through an insulating sealing partition (13), the reaction source area (1a) is externally provided with a first heating structure (11), the epitaxial layer growth area (1b) is externally provided with a second heating structure (12), the gas inlet pipe (21), the gallium boat (22) and the front half of the first uniform gas baffle (23) are located in the reaction source area (1a), the rear half of the first uniform gas baffle (23) and the spraying pipe (24) are located in the epitaxial layer growth area (1b), the oxygen inlet pipe (31) and the front half of the second uniform gas baffle (32) are located in the reaction source area (1a), the rear half of the second uniform gas baffle (32) is located in the epitaxial layer growth area (1b), and the first heating structure (11) and the second heating structure (12) can heat the reaction source area (1a) and the epitaxial layer growth area (1b) respectively, so that the temperatures of the reaction source area (1a) and the epitaxial layer growth area (1b) meet the preset temperature requirements.

4. The epitaxial growth apparatus of claim 3, wherein the apparatus is characterized by: The temperature of the reaction source area (1a) is higher than that of the epitaxial layer growth area (1b).

5. The epitaxial growth equipment for gallium oxide, an ultra-wide bandgap semiconductor material, according to claim 4, is characterized in that: The upper surface of the growth disc (4) is a quartz surface.

6. The epitaxial growth apparatus of gallium oxide as claimed in claim 5, wherein: the substrate is a single crystal substrate; and the substrate is a single crystal substrate having a (0001) plane. The inert gas mixed with oxygen is argon or nitrogen. ​ 7. The epitaxial growth equipment for gallium oxide, an ultra-wide bandgap semiconductor material, according to claim 6, is characterized in that: The driving structure arranged in the growth disc (4) is a rotary motor, and the rotary motor drives the growth disc (4) to rotate.

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