Preparation method and structure of epitaxial β-Ga2O3 thin film on diamond using low temperature pulse layer

Abstract

The present invention relates to a preparation method and structure for epitaxially growing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer. The method comprises: preparing a substrate layer (1); preparing a low-temperature pulse layer (2) on the substrate layer (1); and preparing a thin film layer (3) on the low-temperature pulse layer (2). The present invention solves the problem that β-Ga2O3 cannot be epitaxially grown on a diamond substrate layer at high temperatures. The present invention solves the problem that β-Ga2O3 cannot be epitaxially grown on a diamond substrate at high temperatures. By introducing a low-temperature pulse layer, the present invention greatly reduces the etching effect of oxygen on the substrate. At the same time, the quality of the epitaxial layer is significantly improved, the dislocations and defects of the epitaxial layer are reduced, and the thermal conductivity of the gallium oxide epitaxial layer is significantly improved, providing good material performance support for subsequent gallium oxide heteroepitaxy and high-power and high-frequency power electronic devices.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor devices and relates to a preparation method and structure for epitaxially growing a β-Ga2O3 film on diamond by using a low-temperature pulse layer. Background Art

[0002] As an ultra-wide bandgap semiconductor, β-Ga2O3 exhibits excellent breakdown voltage characteristics for high-power power electronic devices. As the development of new materials accompanies the improvement of device performance, heat dissipation in gallium oxide epitaxial materials is a key issue limiting their power and frequency performance. Furthermore, homogeneous gallium oxide substrates are expensive, while heteroepitaxial gallium oxide can effectively reduce costs. Therefore, exploring high-quality, high-thermal-conductivity epitaxial substrate materials is of great practical value.

[0003] Because diamond substrates are easily etched by oxygen and hydrogen, resulting in numerous etch pits, heteroepitaxial growth of diamond and gallium oxide cannot be achieved through standard methods. During the epitaxial growth of β-Ga2O3, oxygen, as a reaction source, inevitably comes into contact with the substrate material. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, the present invention provides a method and structure for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] An embodiment of the present invention provides a method for preparing a β-Ga2O3 thin film by epitaxial growth on diamond using a low-temperature pulse layer, comprising the following steps:

[0006] preparing a substrate layer;

[0007] preparing a low-temperature pulse layer on the substrate layer;

[0008] A thin film layer is prepared on the low-temperature pulse layer.

[0009] In one embodiment of the present invention, the substrate layer comprises a diamond substrate layer.

[0010] In one embodiment of the present invention, the thin film layer includes a β-Ga2O3 thin film layer.

[0011] In one embodiment of the present invention, preparing a substrate layer includes:

[0012] cleaning the diamond substrate layer;

[0013] The diamond substrate layer is annealed using MOCVD equipment.

[0014] In one embodiment of the present invention, the diamond substrate layer is annealed using an MOCVD device, comprising:

[0015] The cleaned diamond substrate layer is placed in an MOCVD reaction chamber, the nitrogen flow rate is set to 500-2000 sccm, the temperature is set to 600-900° C., and the diamond substrate layer is thermally annealed for 15-30 minutes.

[0016] In one embodiment of the present invention, preparing a low-temperature pulse layer on the substrate layer includes:

[0017] A low-temperature pulse layer is prepared on the diamond substrate layer by using MOCVD equipment.

[0018] In one embodiment of the present invention, a low-temperature pulse layer is prepared on the diamond substrate layer using an MOCVD device, comprising:

[0019] In an MOCVD reaction chamber, the TEGa flow rate is adjusted to 20-60 sccm, the oxygen flow rate is 2000-2600 sccm, the growth temperature is 300-500°C, and the growth pressure is controlled at 35-50 Torr. A low-temperature pulse layer with 50-200 pulses is grown on the diamond substrate layer. Ga and O are introduced successively in each pulse cycle, and the introduction time ratio of Ga to O is 3:1.

[0020] In one embodiment of the present invention, a thin film layer is formed on the low-temperature pulse layer, comprising:

[0021] In the MOCVD reaction chamber, the TEGa flow, oxygen flow and growth pressure are set to be the same as when growing the low-temperature pulse layer, and the growth temperature is set to 600-900°C to grow a β-Ga2O3 thin film layer on the low-temperature pulse layer for 60-90 minutes.

[0022] In one embodiment of the present invention, the thickness of the low-temperature pulse layer is 20-30 nm.

[0023] Another embodiment of the present invention provides a structure for epitaxially growing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer, prepared by the preparation method described in any of the above embodiments, comprising:

[0024] substrate layer;

[0025] a low-temperature pulse layer, the low-temperature pulse layer being located on the substrate layer;

[0026] A thin film layer is located on the low-temperature pulse layer.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention solves the problem of being unable to grow β-Ga2O3 epitaxially on diamond substrates at high temperatures. By introducing a low-temperature pulse layer, this invention significantly reduces the etching effect of oxygen on the substrate. This also significantly improves the quality of the epitaxial layer, reduces dislocations and defects in the epitaxial layer, and significantly increases the thermal conductivity of the gallium oxide epitaxial layer. This provides excellent material performance support for subsequent gallium oxide heteroepitaxial growth and high-power and high-frequency power electronic devices.

[0029] Other aspects and features of the present invention will become apparent from the following detailed description, which proceeds with reference to the accompanying drawings. It should be understood, however, that the drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention, as reference should be made to the appended claims. It should also be understood that, unless otherwise indicated, the drawings are not necessarily drawn to scale and are intended merely to conceptually illustrate the structures and processes described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic flow chart of a method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer according to an embodiment of the present invention;

[0031] Figure 2a-2c A schematic diagram of a process for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer according to an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of a structure for epitaxially growing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0034] Example 1

[0035] See Figure 1 、 Figure 2a-2c , Figure 1 A schematic flow chart of a method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer according to an embodiment of the present invention is provided. Figure 2a-2c A schematic diagram of a process for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulsed layer is provided in an embodiment of the present invention. The present invention provides a method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulsed layer, the method comprising the following steps:

[0036] Step 1: Prepare substrate layer 1, such as Figure 2a shown.

[0037] Preferably, the substrate layer 1 comprises a diamond substrate layer.

[0038] In a specific embodiment, step 1 may include steps 1.1 to 1.2, wherein:

[0039] Step 1.1, cleaning the diamond substrate layer.

[0040] Step 1.2: annealing the diamond substrate layer using MOCVD (Metal-organic Chemical Vapor Deposition) equipment.

[0041] Specifically, the cleaned diamond substrate layer is placed in an MOCVD reaction chamber, the nitrogen flow rate is set to 500-2000 sccm, the temperature is set to 600-900° C., and the diamond substrate layer is thermally annealed for 15-30 minutes.

[0042] Preferably, the nitrogen flow rate is 1050 sccm.

[0043] Preferably, the temperature is 800°C.

[0044] Step 2: prepare a low temperature pulse layer 2 on the substrate layer 1, such as Figure 2b shown.

[0045] Preferably, the thickness of the low-temperature pulse layer 2 is 20-30 nm. A too thin low-temperature pulse layer 2 is insufficient to provide atomic nucleation sites, while an overly thick low-temperature pulse layer 2 will cause a disordered cavity flow field and adversely affect subsequent growth.

[0046] In a specific embodiment, step 2 may specifically include:

[0047] A low-temperature pulse layer 2 is prepared on the diamond substrate layer using an MOCVD device.

[0048] Furthermore, a low-temperature pulse layer 2 is prepared on the substrate layer 1 using an MOCVD device, including:

[0049] In an MOCVD reactor, the TEGa (triethylgallium) flow rate is adjusted to 20-60 sccm, the oxygen flow rate is 2000-2600 sccm, the growth temperature is 300-500°C, and the growth pressure is controlled at 35-50 Torr. A low-temperature pulsed layer 2 is grown on a diamond substrate layer using 50-200 pulses. Within each pulse cycle, Ga and O are introduced sequentially, with a Ga:O ratio of 3:1. Varying the TEGa flow rate and introduction time is not sufficient to obtain a high-quality pre-layer, while minimizing pressure fluctuations and ensuring consistency with subsequent growth conditions ensures continuity during the growth process. Lowering the temperature while using pulses effectively reduces interface defects between the epitaxial gallium oxide layer and the diamond substrate.

[0050] Preferably, the TEGa flow rate is 40 sccm.

[0051] Preferably, the oxygen flow rate is 2300 sccm.

[0052] Preferably, the growth temperature is 300°C.

[0053] Preferably, the growth pressure is 40 Torr.

[0054] Preferably, in each pulse cycle, the time for introducing Ga is 5 seconds and the time for introducing O is 15 seconds.

[0055] Step 3: Prepare a thin film layer 3 on the low temperature pulse layer 2, such as Figure 2c shown.

[0056] Preferably, the thin film layer 3 includes a β-Ga2O3 thin film layer.

[0057] In a specific embodiment, step 3 may specifically include:

[0058] In the MOCVD reaction chamber, the TEGa flow rate, oxygen flow rate and growth pressure are set to be the same as when growing the low-temperature pulse layer 2, which can maintain the continuity of growth parameters, and the growth temperature is set to 600-900°C to grow a β-Ga2O3 thin film layer on the low-temperature pulse layer 2 for 60-90 minutes.

[0059] Preferably, the growth temperature is 800°C.

[0060] Preferably, the growth time is 60 min.

[0061] The present invention proposes first low-temperature growth of a pulsed layer on a diamond substrate. Specifically, prior to high-temperature growth of β-Ga2O3, multiple pulsed layers are grown at low temperatures, each introducing a gallium source and an oxygen source. This significantly reduces the etching effect of oxygen, improves the quality of the epitaxial layer, and facilitates further growth of β-Ga2O3 single crystal thin films. This low-temperature pulsed layer treatment reduces the etching effect of the oxygen source on the diamond substrate, enabling a transition and growth between the diamond substrate and the β-Ga2O3 film. This addresses the inability to heteroepitaxially grow gallium oxide thin films directly on a diamond substrate.

[0062] This invention solves the problem of being unable to grow β-Ga2O3 epitaxially on diamond substrates at high temperatures. By introducing a low-temperature pulse layer, this invention significantly reduces the etching effect of oxygen on the substrate. This also significantly improves the quality of the epitaxial layer, reduces dislocations and defects in the epitaxial layer, and significantly increases the thermal conductivity of the gallium oxide epitaxial layer. This provides excellent material performance support for subsequent gallium oxide heteroepitaxial growth and high-power and high-frequency power electronic devices.

[0063] Example 2

[0064] This embodiment provides the following example based on the method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer provided in the first embodiment. In this embodiment, a β-Ga2O3 thin film layer grown at 800°C is prepared. The preparation method specifically includes:

[0065] Step 1: Perform standard cleaning on the diamond substrate layer, such as Figure 2a shown.

[0066] 1a) Ultrasonic cleaning of the diamond substrate in acetone, ethanol, and deionized water for 10 min.

[0067] 1b) Blow dry the cleaned diamond substrate layer with high-purity nitrogen.

[0068] Step 2: performing thermal annealing on the diamond substrate layer.

[0069] Specifically, the cleaned diamond substrate layer was placed in an MOCVD reaction chamber, the reaction chamber temperature was set to 800° C., the N 2 flow rate was set to 1050 sccm, and the thermal annealing treatment was performed for 15 minutes.

[0070] Step 3, epitaxially grow a low temperature pulse layer of 100 cycles on the diamond substrate layer, such as Figure 2b shown.

[0071] Specifically, the MOCVD chamber temperature was set to 400°C, the growth pressure was set to 40 Torr, the oxygen flow rate was 2300 sccm, and the TEGa flow rate was 40 sccm. A low-temperature pulse layer was epitaxially grown on the diamond substrate layer for 100 cycles, with Ga and O introduced for 5 seconds and 15 seconds in each pulse cycle.

[0072] Step 4, high temperature growth of β-Ga2O3, such as Figure 2c shown.

[0073] Specifically, the other growth parameters were kept unchanged, the temperature was set to 800° C., and the β-Ga 2 O 3 thin film layer was grown for another 60 min.

[0074] Example 3

[0075] See Figure 3 , Figure 3 A schematic diagram of a structure for epitaxially growing a β-Ga2O3 film on diamond using a low-temperature pulsed layer is provided in accordance with an embodiment of the present invention. Based on the above embodiment, the present invention further provides a structure for epitaxially growing a β-Ga2O3 film on diamond using a low-temperature pulsed layer. This structure for epitaxially growing a β-Ga2O3 film on diamond using a low-temperature pulsed layer is prepared using the method for epitaxially growing a β-Ga2O3 film on diamond using a low-temperature pulsed layer as described in the above embodiment. The structure comprises:

[0076] substrate layer 1;

[0077] A low-temperature pulse layer 2, wherein the low-temperature pulse layer 2 is located on the substrate layer 1;

[0078] The thin film layer 3 is located on the low-temperature pulse layer 2 .

[0079] Preferably, the substrate layer 1 comprises a diamond substrate layer.

[0080] Preferably, the thickness of the low-temperature pulse layer 2 is 20-30 nm.

[0081] Preferably, the thin film layer 3 includes a β-Ga2O3 thin film layer.

[0082] This invention solves the problem of being unable to grow β-Ga2O3 epitaxially on diamond substrates at high temperatures. By introducing a low-temperature pulse layer, this invention significantly reduces the etching effect of oxygen on the substrate. This also significantly improves the quality of the epitaxial layer, reduces dislocations and defects in the epitaxial layer, and significantly increases the thermal conductivity of the gallium oxide epitaxial layer. This provides excellent material performance support for subsequent gallium oxide heteroepitaxial growth and high-power and high-frequency power electronic devices.

[0083] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0084] In the description of this specification, reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" means that the specific features, structures, materials, or special features described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or special features described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0085] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer, characterized in that: The following steps are involved: preparing a substrate layer (1), wherein the substrate layer (1) comprises a diamond substrate layer; The method comprises: preparing a low-temperature pulse layer (2) on the substrate layer (1), comprising: using MOCVD equipment to prepare the low-temperature pulse layer (2) on the diamond substrate layer; adjusting the TEGa flow rate to 20-60 sccm, the oxygen flow rate to 2000-2600 sccm, the growth temperature to 300-500° C., and the growth pressure to 35-50 Torr in the MOCVD reaction chamber; and growing the low-temperature pulse layer (2) for 50-200 pulses on the diamond substrate layer, wherein Ga and O are introduced in sequence in each pulse cycle, and the introduction time ratio of Ga to O is 3:1; A thin film layer (3) is prepared on the low-temperature pulse layer (2).

2. The method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer according to claim 1, characterized in that: The thin film layer (3) comprises a β-Ga2O3 thin film layer.

3. The method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer according to claim 1, characterized in that: The substrate layer (1) is prepared, comprising: cleaning the diamond substrate layer; The diamond substrate layer is annealed using MOCVD equipment.

4. The method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer according to claim 3, characterized in that: Annealing the diamond substrate layer using MOCVD equipment, including: The cleaned diamond substrate layer is placed in an MOCVD reaction chamber, the nitrogen flow rate is set to 500-2000 sccm, the temperature is set to 600-900° C., and the diamond substrate layer is thermally annealed for 15-30 minutes.

5. The method for preparing a β-Ga2O3 thin film on diamond using a low temperature pulse layer according to claim 1, characterized in that: Preparing a thin film layer (3) on the low-temperature pulse layer (2), comprising: In the MOCVD reaction chamber, the TEGa flow rate, oxygen flow rate and growth pressure are set to be the same as those when growing the low-temperature pulse layer (2), and the growth temperature is set to 600-900° C. to grow a β-Ga2O3 thin film layer on the low-temperature pulse layer (2) for 60-90 minutes.

6. The method for preparing a β-Ga2O3 thin film on diamond using a low-temperature pulse layer according to claim 1, characterized in that: The thickness of the low-temperature pulse layer (2) is 20-30 nm.

7. A structure for epitaxial growth of β-Ga2O3 thin films on diamond using a low-temperature pulse layer, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6, the structure comprises: substrate layer (1); a low-temperature pulse layer (2), the low-temperature pulse layer (2) being located on the substrate layer (1); A thin film layer (3), wherein the thin film layer (3) is located on the low-temperature pulse layer (2).

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