Mocvd apparatus and method of use and gallium oxide epitaxial film

Abstract

The application relates to the field of gallium oxide epitaxial film processing technology, and particularly discloses a MOCVD device, a use method and a gallium oxide epitaxial film. The MOCVD device comprises a device machine table and a reaction chamber. The device machine table is further provided with an oxygen-carrying gas path and a main pipeline which are in communication with the reaction chamber. The main pipeline is in communication with a gallium source gas path and a doping source gas path. The doping source gas path is in communication with an inorganic silicon source control system. The inorganic silicon source control system comprises an external pipeline which is in communication with the doping source gas path. The external pipeline is in communication with an inorganic silicon source gas path and a dilution gas path. The MOCVD device has the advantages of good stability, simple control, stable dilution inorganic silane flow, adjustable dilution inorganic silane silicon content, and the obtained gallium oxide epitaxial film has the advantages of smooth surface, compactness, high crystalline quality, uniform doping, easy control of doping amount, stable carrier concentration, adjustable carrier concentration, good repeatability, and economic value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gallium oxide epitaxial film processing, and more particularly to a MOCVD device and a use method thereof and a gallium oxide epitaxial film. BACKGROUND

[0002] Gallium oxide is a direct band gap semiconductor material with a band gap of 4.2-5.3eV, which is one of the key materials for manufacturing 110-3000V medium-low voltage low-loss power and 10kW level super-high power power electronic devices. For a device, the carrier concentration of the substrate is one of the most critical parameters, which will seriously affect the function and stability of the device. Homoepitaxy of gallium oxide single crystal wafer as a substrate to obtain low defect and high quality gallium oxide epitaxial film is the key technology for gallium oxide device preparation. Homoepitaxy is beneficial to obtain higher crystalline quality film layer due to avoiding the influence of factors such as lattice mismatch, thermal mismatch and physical property difference between the substrate and the epitaxial layer.

[0003] At present, the preparation method of gallium oxide epitaxial film is mainly metal organic chemical vapor deposition, that is, mainly MOCVD. MOCVD is an epitaxial growth method in which an inert gas is used to transport organic precursors into the reaction chamber, and chemical reactions occur in each reaction zone near and on the surface of the heated substrate, resulting in the deposition of solid materials on the substrate. The gallium source available for MOCVD equipment is trimethyl gallium and triethyl gallium, and the doping source available for MOCVD equipment is tetraethoxysilane, trimethyl aluminum, trimethyl tin, dipentyl magnesium and dipentyl iron, which can provide silicon, aluminum, tin, magnesium and iron doping elements. For silicon element doping, the precursors are all organic substances, which need to be transported into the reaction chamber by carrier gas. During the transportation process, the evaporation amount of the precursors, especially the amount of the doping elements, is difficult to control, and C and H elements are also easily doped during the epitaxial growth process, resulting in inaccurate and uneven doping of the gallium oxide epitaxial film. SUMMARY

[0004] In order to obtain a gallium oxide epitaxial film with uniform doping, the present application provides a MOCVD device and a use method thereof and a gallium oxide epitaxial film.

[0005] In a first aspect, the present application provides a MOCVD device, which adopts the following technical scheme:

[0006] The application relates to a MOCVD device, which comprises a device machine table, a reaction chamber arranged in the device machine table, an oxygen-carrying gas path and a main path communicated with the reaction chamber, an oxygen-carrying flow meter arranged on the oxygen-carrying gas path, a gallium source gas path and a doping source gas path communicated with the main path, a gallium source flow meter arranged on the gallium source gas path, a doping source flow meter arranged on the doping source gas path, oxygen-carrying gas input into the oxygen-carrying gas path, gallium source gas input into the gallium source gas path, and an inorganic silicon source control system communicated with the doping source gas path, wherein the inorganic silicon source control system comprises an external pipe path communicated with the doping source gas path, an inorganic silicon source gas path and a dilution gas path communicated with the external pipe path, an inorganic silicon source flow meter arranged on the inorganic silicon source gas path, and a dilution flow meter arranged on the dilution gas path, inorganic silicon source gas input into the inorganic silicon source gas path, and dilution gas input into the dilution gas path.

[0007] By adopting the technical scheme, the inorganic silicon source control system is externally connected to the doping source gas path on the basis of the original device machine table, the inorganic silicon source gas and the dilution gas in the inorganic silicon source control system can be mixed in the external pipe path to obtain diluted inorganic silicon, the diluted inorganic silicon contains a certain amount of silicon, and then the diluted inorganic silicon enters the device machine table through the doping source gas path. Then, the diluted inorganic silicon and the gallium source gas are mixed and form a mixed gas by using the original operation program of the device machine table, and the mixed gas enters the reaction chamber. At the same time, the mixed gas and the oxygen-carrying gas chemically react in the high-temperature reaction chamber, the inorganic silicon source gas and the gallium source gas are uniformly mixed and grown in a large area, and the gallium oxide epitaxial film doped with silicon is obtained. The process is simple, easy to operate and controllable. Moreover, the flow rates of the inorganic silicon source gas path and the dilution gas path can be adjusted according to requirements, the flow rates of the inorganic silicon source gas and the dilution gas are controlled, the silicon content in the diluted inorganic silicon is stable and controllable, the gallium oxide epitaxial film with different silicon doping amounts is further obtained, and the carrier concentration of the gallium oxide epitaxial film can be regulated between 3.504*10 17 -1.026*10 20 cm -3 , which can be used for batch commercial production and has economic value.

[0008] The MOCVD device provided by the application only needs to externally connect the inorganic silicon source control system to the original doping source gas path of the device machine table, does not need to greatly change the MOCVD device, has the advantages of good stability, simple operation, stable diluted inorganic silicon flow rate, adjustable silicon content in the diluted inorganic silicon, and is convenient to apply. Meanwhile, it is found through experiments that the gallium oxide epitaxial film obtained by using the MOCVD device has a smooth and dense surface, high crystalline quality, uniform doping, easy-to-control doping amount, stable carrier concentration, adjustable carrier concentration and good repeatability.

[0009] Optionally, the external pipeline is also communicated with a pressure relief gas path, and a pressure control meter is arranged on the pressure relief gas path.

[0010] By adopting the above technical scheme, in order to prevent the diluted inorganic silane from gathering in the gas path to cause pressure to be too high and affect the flow of the equipment, a pressure relief gas path is arranged on the external pipeline, so that when the pressure of the diluted inorganic silane is too high, the pressure relief gas path can be used for pressure relief, thereby ensuring the stability of the diluted inorganic silane entering the equipment.

[0011] In a second aspect, the application provides a use method of the MOCVD equipment, and the following technical scheme is adopted:

[0012] The flow of the inorganic silicon source flow meter is 1-100 sccm, and the flow of the dilution flow meter is 100-1000 sccm. Preferably, the flow of the inorganic silicon source flow meter is 1-67.4 sccm.

[0013] By adopting the above technical scheme, the flow of the inorganic silicon source flow meter and the flow of the dilution flow meter are limited, so as to facilitate the adjustment of the inorganic silicon source gas flow and the dilution gas flow, and then the gallium oxide epitaxial film with different silicon doping amounts is obtained.

[0014] Optionally, the inorganic silicon source is a mixed gas of disilane and argon, the content of disilane in the inorganic silicon source is 90-110 ppm at normal temperature and pressure, and the dilution gas is argon. Preferably, the content of disilane in the inorganic silicon source is 100 ppm.

[0015] By adopting the above technical scheme, the inorganic silicon source is limited, the raw material is easy to obtain, and the content of disilane in the inorganic silicon source is 90-110 ppm, which will not occur naturally when it contacts with oxygen. The disilane is used as a gaseous inorganic silicon source, which can contact with oxygen in a high-temperature reaction chamber, chemically react, and replace part of gallium sites while generating gallium oxide, so as to obtain a silicon-doped gallium oxide epitaxial film.

[0016] At the same time, the dilution gas is also limited, argon is easy to obtain, and argon is an inert gas with stable chemical properties, which will not chemically react by itself, nor will it chemically react with gallium or oxygen, thereby ensuring the purity of the gallium oxide epitaxial film and increasing the stability of the electrical properties of the gallium oxide epitaxial film.

[0017] Further, the argon is high-purity argon, and the purity of the high-purity argon is 5N.

[0018] Optionally, the pressure of the pressure control meter is 170-190 KPa. Preferably, the pressure of the pressure control meter is 180 KPa.

[0019] By adopting the technical scheme, when the pressure of the diluted inorganic silane gathered in the gas path is greater than 170-190 KPa, the pressure relief is started, and the operation and control of the inorganic silicon source control system are facilitated.

[0020] Optionally, the gallium source flowmeter is connected to a gallium flow of 9.665*10 -7 -1.41*10 -4 mol / min.

[0021] Optionally, the molar ratio of silicon / gallium in the reaction chamber is 6.97*10 -10 -8.398*10 -6 , and the molar ratio of oxygen / gallium in the reaction chamber is 1000-2500.

[0022] By adopting the technical scheme, the amount of silicon / gallium and oxygen introduced into the reaction chamber is limited, so that the silicon / gallium and oxygen can be chemically reacted and form a gallium oxide epitaxial film.

[0023] Further, the oxygen-carrying flowmeter introduces an oxygen flow of 0.001-0.27 mol / min.

[0024] Optionally, the gallium source gas is a mixed gas of organic gallium and argon, and the content of organic gallium in the gallium source gas is 400-9000 ppm at normal temperature and pressure; and the oxygen-carrying gas is oxygen.

[0025] Further, the oxygen is high-purity oxygen, and the purity of the high-purity oxygen is 6N.

[0026] Optionally, the organic gallium is one or both of trimethyl gallium and triethyl gallium.

[0027] In a third aspect, the application provides a gallium oxide epitaxial film, which adopts the following technical scheme:

[0028] A gallium oxide epitaxial film is prepared by using the MOCVD equipment described above, and the carrier concentration of the gallium oxide epitaxial film ranges from 3.504*10 17 -1.026*10 20 cm -3 .

[0029] In summary, the application has at least the following beneficial effects:

[0030] 1、The MOCVD equipment of the application only needs to externally connect an inorganic silicon source control system on the original doping source gas path of the equipment machine, mixes the inorganic silicon source gas and the dilution gas to obtain dilution inorganic silane, then mixes the dilution inorganic silane and the gallium source gas to form a mixed gas, and then the mixed gas and the oxygen carrying gas chemically react in the high-temperature reaction chamber, so that the inorganic silicon source gas and the gallium source gas are uniformly mixed and large-area growth is realized, and a gallium oxide epitaxial film with doped silicon is obtained. Silicon can fully replace part of the gallium in the gallium oxide molecules to provide more electron donors for the gallium oxide epitaxial film, so as to achieve the purpose of carrier regulation. The obtained gallium oxide epitaxial film has a smooth, dense and good crystalline surface, uniform doping, stable performance and good repeatability, and the carrier concentration of the gallium oxide epitaxial film can be regulated between 3.504 x 1018 17 20 cm-3 and 1.026 x 1018 -3 , which can be used for batch commercial production and has economic value.

[0031] 2、The MOCVD equipment of the application only needs to externally connect an inorganic silicon source control system on the original doping source gas path of the equipment machine, without the need to make major changes to the MOCVD equipment, and has the advantages of good stability, simple operation, stable dilution inorganic silane flow, adjustable dilution inorganic silane silicon content, and is easy to apply. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of the MOCVD equipment of the application.

[0033] Figure 2 is a curve of the carrier concentration of the gallium oxide epitaxial film changing with the silicon / gallium molar ratio.

[0034] BRIEF DESCRIPTION OF DRAWINGS: 1, equipment machine; 2, reaction chamber; 3, oxygen carrying gas path; 4, main pipe; 5, gallium source gas path; 6, doping source gas path; 71, external pipe; 72, inorganic silicon source gas path; 73, dilution gas path; 74, pressure relief gas path. DETAILED DESCRIPTION

[0035] In order to make the application easier to understand, the application will be further described in detail below in conjunction with examples, which only serve to illustrate the application and are not limited to the scope of the application. The raw materials or components used in the application can be obtained by commercial means or conventional methods if not otherwise specified.

[0036] Gallium oxide is an ultra-wide bandgap semiconductor material after silicon, germanium, silicon carbide and gallium nitride, and has great application potential in the field of power electronic devices such as Schottky diodes, field effect transistors, charging and discharging circuits, etc.

[0037] EMBODIMENT

[0038] ​​​A MOCVD apparatus, as shown in the figure, comprises an apparatus machine 1, a reaction chamber 2 arranged in the apparatus machine 1, an oxygen-carrying gas path 3 and a main path 4 arranged on the apparatus machine 1 and communicated with the reaction chamber 2. Figure 1

[0039] The oxygen-carrying gas path 3 is provided with a pneumatic valve and an oxygen-carrying flowmeter. The oxygen-carrying gas path 3 is connected with oxygen-carrying gas, and the oxygen-carrying gas is high-purity oxygen with a purity of 6N.

[0040] The main path 4 is communicated with a gallium source gas path 5 and a doping source gas path 6. The gallium source gas path 5 is provided with a pneumatic valve and a gallium source flowmeter. The gallium source gas path 5 is connected with gallium source gas, and the gallium source gas is argon carrying organic gallium, and the organic gallium is trimethyl gallium. The content of the organic gallium in the gallium source gas is 2000ppm at normal temperature and pressure. The gallium source flowmeter is connected with a gallium flow of 9.665×10 -7 -1.41×10 -4 mol / min. The molar ratio of silicon / gallium in the reaction chamber 2 is 6.97×10 -10 -8.398×10 -6 The molar ratio of oxygen / gallium in the reaction chamber is 1000-2500.

[0041] The doping source gas path 6 is provided with a pneumatic valve and a doping source flowmeter. The doping source gas path 6 is connected with diluted inorganic silane.

[0042] The doping source gas path 6 is communicated with an inorganic silicon source control system outside the apparatus machine. The inorganic silicon source control system comprises an external pipe 71 communicated with the doping source gas path 6. The external pipe 71 is communicated with an inorganic silicon source gas path 72, a dilution gas path 73 and a pressure relief gas path 74. The pressure relief gas path 74 is provided with a pneumatic valve and a pressure control meter, and the pressure of the pressure control meter is 180KPa.

[0043] The inorganic silicon source gas path 72 is provided with a pneumatic valve and an inorganic silicon source flowmeter. The inorganic silicon source gas path 72 is connected with inorganic silicon source gas, and the inorganic silicon source is argon carrying ethylsilane. The content of the ethylsilane in the inorganic silicon source is 100ppm at normal temperature and pressure. The inorganic silicon source flowmeter is connected with a flow of 1-100sccm.

[0044] The dilution gas path 73 is provided with a pneumatic valve and a dilution flowmeter. The dilution gas path 73 is connected with dilution gas, and the dilution gas is high-purity argon with a purity of 5N. The dilution flowmeter is connected with a flow of 100-1000sccm.

[0045] ​First, the inorganic silicon source gas and the dilution gas are mixed in the external pipeline 71 to form diluted inorganic silane. Then the diluted inorganic silane enters the doping source gas pipeline 6, and the diluted inorganic silane is controlled by the doping source flow meter, and the gallium source gas is controlled by the gallium source flow meter, so that the diluted inorganic silane and the gallium source gas are quantitatively mixed in the main pipeline 4 to form a mixed gas, and at the same time, the mixed gas and the oxygen-carrying gas are quantitatively mixed by the control of the oxygen-carrying flow meter, and a chemical reaction occurs in the high-temperature reaction chamber 2. The temperature of the reaction chamber is 750℃, the reaction time is 15min, the substrate is Fe-doped β-Ga2O3 substrate <010>, and a doped gallium oxide epitaxial film is obtained. The thickness of the gallium oxide epitaxial film is 0.25μm.

[0046] Because the diluted inorganic silane and the gallium source gas are mixed sufficiently before entering the reaction chamber 2, silicon can fully replace part of the gallium in the gallium oxide molecules to provide more electron donors for the gallium oxide epitaxial film, achieving the purpose of carrier regulation. The obtained gallium oxide epitaxial film has a smooth, dense, and good crystalline surface, uniform doping, stable performance, and good repeatability, and can be used for batch commercial production, having economic value.

[0047] Application example

[0048] Application example 1-7

[0049] A gallium oxide epitaxial film is obtained by using the MOCVD equipment of the embodiment and limiting the related parameters of the MOCVD equipment, i.e., limiting the inorganic silicon source flow, the dilution argon flow, the gallium source flow, and the oxygen-carrying flow. The related parameters of the MOCVD equipment and the carrier concentration of the gallium oxide epitaxial film measured by the Hall effect are shown in Table 1.

[0050] Table 1 MOCVD equipment and use method and gallium oxide epitaxial film

[0051]

[0052]

[0053] In combination with Table 1, a curve of the carrier concentration of the gallium oxide epitaxial film changing with the silicon / gallium molar ratio is drawn, and the change curve is shown in Figure 2 .

[0054] From the change curve in Figure 2 , it can be seen that the carrier concentration can be regulated between 3.504×10 17 -1.026×10 20 cm -3 with the change of the amount of silicon atoms doped into the gallium oxide epitaxial film. The silicon / gallium molar ratio is ≤4.77×10 -8When the silicon atom incorporation amount is increased, the carrier concentration is increased; the silicon / gallium molar ratio is ≥4.77×10 -8 When the silicon atom incorporation amount is increased, the carrier concentration is gradually decreased. This is probably due to the oxidation of part of the silicon atoms, and the change conforms to the change rule of the Lorentz equation.

[0055] It can be seen from Table 1 and Figure 2 It can be seen from Table 1 and It can be seen from Table 1 and

[0056] It can be seen from Table 1 and 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm -3 between 3.504×10 17 -1.026×10 20 cm <000002

Claims

1. A MOCVD device, comprising a device machine (1), a reaction chamber (2) arranged in the device machine (1), an oxygen carrier gas path (3) and a main gas path (4) arranged on the device machine (1) and communicating with the reaction chamber (2), an oxygen carrier flow meter arranged on the oxygen carrier gas path (3), a gallium source gas path (5) and a doping source gas path (6) communicating with the main gas path (4), a gallium source flow meter arranged on the gallium source gas path (5), and a doping source flow meter arranged on the doping source gas path (6), the oxygen carrier gas path (3) being connected to an oxygen carrier gas, and the gallium source gas path (5) being connected to a gallium source gas, characterized in that: The doping source gas path (6) is communicated with an inorganic silicon source control system, the inorganic silicon source control system comprises an external pipeline (71) communicated with the doping source gas path (6), the external pipeline (71) is communicated with an inorganic silicon source gas path (72) and a dilution gas path (73), the inorganic silicon source gas path (72) is provided with an inorganic silicon source flow meter, the dilution gas path (73) is provided with a dilution flow meter, the inorganic silicon source gas path (72) is communicated with inorganic silicon source gas, and the dilution gas path (73) is communicated with dilution gas; The flow rate of the inorganic silicon source flow meter is 1-100sccm, the flow rate of the dilution flow meter is 100-1000sccm, the inorganic silicon source gas is a mixture of disilane and argon, the content of disilane in the inorganic silicon source is 90-110ppm at normal temperature and pressure, and the dilution gas is argon; the gallium source gas is a mixture of organic gallium and argon, the content of organic gallium in the gallium source gas is 400-9000ppm at normal temperature and pressure, and the oxygen-carrying gas is oxygen; The molar ratio of silicon / gallium in the reaction chamber (2) is 6.97 x 10 -10 -8.398 x 10 -6 The molar ratio of oxygen / gallium in the reaction chamber (2) is 1000-2500.

2. The MOCVD apparatus according to claim 1, wherein: The external pipeline (71) is further communicated with a pressure relief gas path (74), and the pressure relief gas path (74) is provided with a pressure control meter.

3. The MOCVD apparatus according to claim 1, wherein: The pressure of the pressure control meter is 170-190KPa. ​ 4. The MOCVD apparatus according to claim 1, wherein: The gallium source flowmeter is connected to a gallium flow of 9.665 x 10 -7 -1.41 x 10 -4 mol / min.

5. The MOCVD apparatus according to claim 1, wherein: The organic gallium is one or both of trimethyl gallium and triethyl gallium.

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