A method for preparing a GaON epitaxial film grown by plasma-enhanced chemical vapor deposition

Abstract

The application relates to the field of semiconductor material preparation, in particular to a preparation method of a GaON epitaxial film prepared through plasma-enhanced chemical vapor deposition (PECVD). The GaON epitaxial film is prepared by taking metal gallium as a gallium source, taking oxygen as an oxygen source, taking nitrogen as a nitrogen source and taking argon as a transport gas. The GaON epitaxial film is prepared by optimizing post-growth parameters through a PECVD system. The method can make gaseous substances containing film components chemically react through glow discharge plasma, and then realize film material growth. Since a large number of high-energy electrons are contained in the plasma, the high-energy electrons can provide the activation energy required by the chemical vapor deposition process, so that the reaction temperature is significantly reduced, and the efficiency and quality of film deposition are improved. The GaON epitaxial film prepared through the method has excellent performance and meets the needs of future industrialized mass production.

Description

Technical Field

[0001] This invention belongs to the field of semiconductors, specifically relating to a method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition. Background Technology

[0002] GaON, a transparent conductive oxide, is a novel wide-bandgap semiconductor. Compared to third-generation semiconductors such as GaN and SiC, it boasts significant advantages, including a larger bandgap and lower growth cost. Compared to β-Ga₂O₃, GaON has a lower oxygen vacancy concentration and avoids the challenges of intrinsic carrier modulation, p-type doping, and stable Schottky contacts. GaON epitaxial films are grown using anion alloying engineering based on valence band hybridization. This allows for the use of N 2p and O 2p orbital hybridization to increase the valence band top position of β-Ga₂O₃, thereby shielding the impurity energy levels of oxygen vacancies and effectively suppressing their impact. Furthermore, it reduces the effective hole mass of β-Ga₂O₃, thus improving hole mobility. Optoelectronic devices fabricated from GaON epitaxial films exhibit lower dark current and faster response times compared to β-Ga₂O₃ optoelectronic devices.

[0003] Plasma-enhanced chemical vapor deposition (PECVD) is one of the practical methods for growing GaON epitaxial films, suitable for future industrial mass production. PECVD is a fabrication technique that uses glow discharge plasma to induce a chemical reaction in gaseous substances containing the film composition, thereby achieving film material growth. Because plasma contains a large number of high-energy electrons, they can provide the activation energy required for the chemical vapor deposition process. Simultaneously, the collisions between electrons and gas molecules promote the decomposition, combination, excitation, and ionization of gas molecules, generating highly reactive chemical groups. This significantly reduces the temperature range of the film deposition process, allowing deposition processes that previously required high temperatures to be performed at lower temperatures, thus improving the efficiency and quality of film deposition. Summary of the Invention

[0004] To address the problems existing in this field, the purpose of this invention is to propose a method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition with low growth temperature, fast growth rate, and high crystallinity.

[0005] The technical solution for achieving the objective of this invention is as follows:

[0006] This invention uses mature sapphire single crystal as a substrate and employs plasma-enhanced chemical vapor deposition (PECVD) to epitaxially grow GaON thin films on the sapphire substrate. The glow discharge plasma, with its large number of high-energy electrons, provides the activation energy required for the PECVD process. Simultaneously, the collisions between electrons and gas molecules promote the decomposition, combination, excitation, and ionization of gas molecules, generating highly reactive chemical groups. This enhances the substrate's activity, significantly reducing the reaction temperature and improving the efficiency and quality of thin film deposition.

[0007] The method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition according to the present invention comprises the following steps:

[0008] Step (1): Place the gallium source and the cleaned and dried substrate into the reaction boat, which is then placed inside a quartz reaction tube;

[0009] Step (2): Seal the quartz reaction tube and turn on the vacuum pump to evacuate the quartz tube; when the vacuum degree of the quartz tube is below 1 Pa, open the valve of the mixing tank and introduce inert argon gas as the transport carrier gas.

[0010] Step (3): Heat the reaction boat and substrate inside the quartz tube; when the temperature rises to the set temperature, open the oxygen and nitrogen valves, adjust the oxygen and nitrogen flow rates, and let oxygen and nitrogen enter the quartz tube to participate in the reaction;

[0011] Step (4): Turn on the RF power supply, set the RF power and growth time, and deposit a GaON thin film on the substrate to complete the preparation.

[0012] Preferably, the sapphire substrate is ultrasonically cleaned sequentially in acetone, ethanol, and plasma water, and then dried using N2.

[0013] Preferably, the gallium source is metallic gallium particles with a purity of 99.999%. The oxygen gas flow rate ranges from 1 to 100 sccm, the nitrogen gas flow rate ranges from 1 to 100 sccm, and the argon gas flow rate ranges from 10 to 100 sccm.

[0014] Preferably, the substrate is a (0001)-plane sapphire substrate.

[0015] Preferably, the polished surface of the sapphire substrate is placed upside down inside the ceramic boat.

[0016] Preferably, the gallium source and the substrate need to be kept at a certain distance to avoid contaminating the substrate and affecting the film quality.

[0017] More preferably, the reaction boat in which the gallium source is placed is 4cm-12cm away from the substrate surface.

[0018] Preferably, the deposition temperature of the thin film is between 700°C and 1000°C.

[0019] Preferably, the radio frequency power is between 0W and 300W.

[0020] The beneficial effects of this invention are as follows: 1) GaON thin films are prepared by plasma-enhanced vapor deposition using readily available industrial raw material gallium and commercially available sapphire substrates; 2) The activity of the substrate is improved by using glow discharge plasma, which significantly reduces the reaction temperature and improves the efficiency and quality of film deposition; 3) High-quality GaON epitaxial thin films can be prepared by optimizing growth conditions; 4) The equipment used is simple, does not require expensive raw materials, rare substrate materials or intercalation layer materials, or additional special energy, and has the potential for large-scale industrial production. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the PECVD system used in this invention for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition.

[0023] Figure 2 This is an X-ray diffraction pattern of a GaON epitaxial thin film prepared on a sapphire substrate according to Embodiment 1 of the present invention.

[0024] Figure 3 This is an XPS image of the GaON epitaxial film prepared on a sapphire substrate in Embodiment 1 of the present invention. Detailed Implementation

[0025] To better illustrate the content of this invention, the following description is provided in conjunction with the accompanying drawings and examples:

[0026] like Figure 1 As shown, this invention discloses a method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition, the specific steps of which include:

[0027] Step (1) Place the gallium source and the cleaned and dried substrate into the reaction boat, and place the reaction boat into the quartz reaction tube;

[0028] Step (2) Seal the quartz reaction tube and turn on the vacuum pump to evacuate the quartz tube; when the vacuum degree of the quartz tube is below 1 Pa, open the valve of the mixing tank and introduce inert argon gas as the transport carrier gas.

[0029] Step (3) Heat the reaction boat and substrate inside the quartz tube; when the temperature rises to the set temperature, open the oxygen and nitrogen valves, adjust the oxygen and nitrogen flow rates, and let oxygen and nitrogen enter the quartz tube to participate in the reaction;

[0030] Step (4) Turn on the RF power supply, set the RF power and growth time, and deposit a GaON thin film on the substrate to complete the preparation.

[0031] The sapphire substrate was ultrasonically cleaned in acetone, ethanol and plasma water in sequence, and then dried with N2.

[0032] The gallium source is metallic gallium particles with a purity of 99.999%. The oxygen gas flow rate ranges from 1 to 100 sccm, the nitrogen gas flow rate ranges from 1 to 100 sccm, and the argon gas flow rate ranges from 10 to 100 sccm.

[0033] The substrate is a (0001)-faceted sapphire substrate, with the polished surface of the sapphire substrate placed upside down inside a ceramic boat.

[0034] The reaction boat containing the gallium source is placed 4cm-12cm away from the substrate surface.

[0035] The deposition temperature of the thin film is between 700℃ and 1000℃.

[0036] Radio frequency power ranges from 0W to 300W.

[0037] The sapphire substrate used in the examples is (0001)-plane Al2O3 with a thickness of approximately 430±15nm, single-sided polished, and the surface roughness is ≤0.3nm.

[0038] To further illustrate the present invention, the following detailed description of a method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition provided by the present invention is provided in conjunction with embodiments, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] A method for growing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition, the preparation method of which is as follows:

[0041] Gallium particles ranging from 0.5mm to 2mm in size were placed in a reaction boat, which was then placed inside a quartz reaction tube. A cleaned and dried c-side sapphire substrate was placed in a ceramic boat, which was then placed inside the quartz reaction tube. The reaction boat was 8cm away from the substrate. Argon gas was introduced as both carrier and protective gas, while oxygen and nitrogen were introduced as reactant gases through the quartz reaction tube. The temperature was set at 800℃, the RF power at 150W, and the growth time was 90 minutes, depositing a GaON thin film on the substrate. Figure 2The powder XRD diffraction pattern shows that, in addition to the diffraction peaks of the sapphire substrate at 36.2°, 41.6°, and 44.3°, the other four peaks are multiple diffraction peaks of the (100), (006), (103), and (104) crystal planes of GaON, indicating that the prepared GaON epitaxial film is a single crystal material.

[0042] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. For those skilled in the art, any modifications, equivalent substitutions, or improvements made based on the above description and within the methods and principles of this invention should be included within the scope of protection of this invention. It is neither necessary nor possible to exhaustively describe all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition, characterized in that, Includes the following steps: Step (1) Place the gallium source and the cleaned and dried substrate into the reaction boat, which is then placed inside a quartz reaction tube; Step (2) Seal the quartz reaction tube and turn on the vacuum pump to evacuate the quartz tube; when the vacuum degree of the quartz tube is below 1 Pa, open the valve of the mixing tank and introduce inert argon gas as the transport carrier gas. Step (3) Heat the reaction boat and substrate inside the quartz tube; when the temperature rises to the set temperature, open the oxygen and nitrogen valves, adjust the oxygen and nitrogen flow rates, and let oxygen and nitrogen enter the quartz tube to participate in the reaction; Step (4) Turn on the RF power supply, set the RF power and growth time, and deposit a GaON thin film on the substrate to complete the preparation; The gallium source is metallic gallium particles with a purity of 99.999%, and the oxygen gas flow rate ranges from 1 to 100 sccm, the nitrogen gas flow rate ranges from 1 to 100 sccm, and the argon gas flow rate ranges from 10 to 100 sccm. The substrate is a sapphire substrate with a (0001) facet; The deposition temperature of the thin film is between 700 ℃ and 1000 ℃; The radio frequency power ranges from 150 W to 300 W.

2. The method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition as described in claim 1, characterized in that, The substrate is ultrasonically cleaned with one or more of acetone, anhydrous ethanol, and deionized water, and then dried with high-purity nitrogen.

3. The method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition as described in claim 2, characterized in that, The polished surface of the sapphire substrate is placed upside down inside the ceramic boat.

4. The method for preparing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition as described in claim 1, characterized in that, The gallium source is placed 4 cm-12 cm away from the substrate surface.

5. A method for growing GaON epitaxial thin films by plasma-enhanced chemical vapor deposition, characterized in that, It is prepared by the method for preparing GaON epitaxial thin films according to any one of claims 1-4.

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