Method for manufacturing semiconductor thin film and method for manufacturing semiconductor device
The mist CVD process forms semiconductor thin films with indium and aluminum on Ga2O3 substrates, addressing lattice constant issues to enhance band offsets and device performance, and simplifying the manufacturing process.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NAT UNIV KYOTO INST OF TECH
- Filing Date
- 2025-12-22
- Publication Date
- 2026-07-02
AI Technical Summary
Existing methods for manufacturing semiconductor devices face limitations in increasing the band offset between epitaxial semiconductor layers due to lattice constant differences, constraining the ability to enhance device performance.
A method involving the use of a mist CVD process to form semiconductor thin films on a Ga2O3 substrate, incorporating indium and aluminum, allowing for larger band gaps and improved lattice matching, thereby increasing the band offset and design flexibility.
The method enables the formation of semiconductor thin films with enhanced band offsets, improving device performance and reducing defects, while simplifying the manufacturing process by eliminating the need for a vacuum atmosphere.
Smart Images
Figure JP2025044716_02072026_PF_FP_ABST
Abstract
Description
Method for manufacturing a semiconductor thin film and method for manufacturing a semiconductor device
[0001] The present invention relates to a method for manufacturing a semiconductor thin film and a method for manufacturing a semiconductor device.
[0002] Ga ２ O ３ On a substrate formed of a binary metal oxide of, an epitaxial semiconductor layer formed of a binary metal oxide crystal of Ga ２ O ３ and an epitaxial semiconductor layer composed of a ternary metal oxide composition crystal of (Al ｘ Ga １－ｘ ) ２ O ３ have been proposed to be laminated (see, for example, Patent Document 1). In such a device, by increasing the band gap of the epitaxial semiconductor layer formed from the (Al ２ O ３ crystal with respect to the epitaxial semiconductor layer formed from the Ga ｘ Ga １－ｘ ) ２ O ３ crystal, it is required to improve the performance of the device by designing a large band offset at the interface of these epitaxial semiconductor layers.
[0003] Japanese Patent Application Laid-Open No. 2023-525101
[0004] By the way, in the manufacture of the device described in Patent Document 1, in order to increase the above-mentioned band offset, it is conceivable to increase the band gap of the epitaxial semiconductor layer formed from the (Al ｘ Ga １－ｘ ) ２ O ３ crystal by approaching the composition ratio of Al in the epitaxial semiconductor layer to 1. However, in the case of an epitaxial semiconductor layer formed from (Al ｘ Ga １－ｘ ) ２ O ３ as the composition ratio of Al approaches 1, the difference in lattice constant from the epitaxial semiconductor layer formed from Ga ２ O ３ increases. Therefore, the composition ratio of Al is Ga２ O ３ (Al ｘ Ga １－ｘ ) ２ O ３ The number of defects in the epitaxial semiconductor layer is constrained to a range where the lattice constant difference is within an acceptable range. Therefore, there was a limit to improving device performance by increasing the band offset.
[0005] This invention has been made in view of the above-mentioned reasons, and aims to provide a method for manufacturing a semiconductor thin film and a method for manufacturing a semiconductor device that can increase the degree of design freedom for improving the performance of a semiconductor device.
[0006] The semiconductor thin film manufacturing method according to the present invention is Ga ２ O ３ The process includes the steps of preparing a substrate formed from crystals and forming a semiconductor thin film on the substrate using a mist CVD method, which consists of a semiconductor crystal containing indium and aluminum.
[0007] From another perspective, the method for manufacturing a semiconductor device according to the present invention is as follows: Ga on a substrate ２ O ３ The method includes the steps of: forming a first semiconductor crystal layer made of crystals; forming a second semiconductor crystal layer made of semiconductor crystals containing indium and aluminum on the first semiconductor crystal layer by a mist CVD method; and forming a highly doped region by implanting Si elements into the second semiconductor crystal layer from the side opposite to the first semiconductor crystal layer.
[0008] According to the present invention, Ga ２ O ３ A substrate formed from crystal contains at least indium and aluminum, and Ga ２ O ３ Within the range where the degree of lattice matching with the crystal falls within an acceptable range, (Al ｘ Ga １－ｘ ) ２ O ３ It is possible to form semiconductor thin films made of semiconductor crystals with a larger band gap compared to crystalline semiconductors. Therefore, (Alｘ Ga １－ｘ ) ２ O ３ Compared to semiconductor thin films made of crystals, Ga ２ O ３ Since the band offset at the interface with the crystal can be increased, the design flexibility for improving the performance of semiconductor devices by increasing the band offset can be enhanced accordingly.
[0009] This is a schematic diagram of the mist CVD apparatus according to Embodiment 1. This is a diagram showing an example of a schematic diagram of a semiconductor device according to Embodiment 2. This is a diagram for explaining the performance of the semiconductor device according to Embodiment 2. This is a diagram showing the XRD results for the sample according to Example 1. This is a diagram showing the reciprocal lattice map of the sample according to Example 1. This is a diagram showing the AFM image of the sample surface according to Example 1. This is a TEM image of the cross-section of the sample according to Example 1. This is a magnified TEM image of the area enclosed by the rectangular frame 1 in Figure 5A. This is a magnified TEM image of the area enclosed by the rectangular frame 2-1 in Figure 5B. This is a magnified TEM image of a part of the TEM image shown in Figure 6A. This is a magnified TEM image of the area enclosed by the rectangular frame 2-2 in Figure 5B. This is a magnified TEM image of a part of the TEM image shown in Figure 7A. This is a magnified TEM image of the area enclosed by the rectangular frame 3 in Figure 5B. This is a magnified TEM image of a part of the TEM image shown in Figure 8A. This is a diagram showing the electron diffraction pattern in a relatively near-surface portion of the semiconductor thin film of the sample according to Example 1. This figure shows the electron diffraction pattern at the boundary between the semiconductor thin film and the substrate of the sample according to Example 1. This figure shows the XRD results for each of the samples according to Examples 2 to 5.
[0010] (Embodiment 1) Hereinafter, a method for manufacturing a semiconductor thin film according to an embodiment of the present invention will be described with reference to the drawings. In the method for manufacturing a semiconductor thin film according to this embodiment, a semiconductor thin film is formed on a substrate. Here, the substrate is Ga ２ O ３ A substrate formed from crystal is used. ２ O ３ If the substrate is not made from a crystal, at least the surface on which the semiconductor thin film is formed must be flat and have Ga on the surface.２ O ３ Materials with exposed crystal layers can be used.
[0011] A semiconductor thin film consists of a semiconductor crystal containing at least indium and aluminum. Specifically, a semiconductor thin film is made of (In ｘ Al １－ｘ ) ２ O ３ Crystal (0<x<1), (In ｘ Al １－ｘ ) ｙ Ga ２ーｙ O ３ It consists of crystals (0 < x < 1, 0 < y < 1), etc.
[0012] In the semiconductor thin film manufacturing method according to this embodiment, the mist CVD (Chemical Vapor Deposition) method is used to produce Ga ２ O ３ A semiconductor thin film made of a semiconductor crystal containing at least indium and aluminum is deposited on a substrate formed from a material. Here, for example, a mist CVD apparatus as shown in Figure 1 is used. This mist CVD apparatus comprises gas supply sources 21, 24, flow rate adjustment mechanisms 22, 25, flow meters 23, 26, a raw material supply container 31, a water storage container 33, an ultrasonic transducer 35, and a reaction vessel 41. The reaction vessel 41 has a storage section 412 provided with a storage chamber S12 for temporarily storing mist-like raw materials with a particle size of about 3 μm, and a film deposition section 411 provided with a film deposition chamber S11 that communicates with the storage chamber S12 and has the substrate W placed inside. The film deposition section 411 also has a heater 42 for heating the substrate W placed in the film deposition chamber S11. Here, the deposition chamber S11 is set such that, with the substrate W placed on the mounting section 411a, the distance between the surface of the substrate W and the inner wall 411b facing the mounting section 411a is approximately 1 mm. This allows a laminar flow of mist-like raw materials to be formed on the deposition surface side of the substrate W during the deposition of the semiconductor thin film.
[0013] The gas supply source 21 that supplies the carrier gas and the raw material supply container 31 are connected via a first gas supply pipe P1. The raw material supply container 31 and the reaction vessel 41 are connected via a second gas supply pipe P2. In addition, a third gas supply pipe P3, which is connected to the gas supply source 24 that supplies the raw material dilution gas, is connected to the second gas supply pipe P2. Furthermore, the reaction vessel 41 is connected to an exhaust pipe P4 for discharging excess gas from within the reaction vessel 41.
[0014] The raw material supply container 31 stores a raw material solution 32 obtained by dissolving precursor raw materials for oxides that form semiconductor thin films in a solvent. Examples of precursor raw materials for oxides that form semiconductor thin films include a first compound of indium and one or more alcohol compounds selected from alcohol compounds, and a second compound of aluminum and one or more alcohol compounds selected from alcohol compounds. The first compound is, for example, indium acetylacetonate (In(C) ５ H ７ O ２ ) ３ ) is also an example of the second compound, aluminum acetylacetone (Al(C)). ５ H ７ O ２ ) ３ Furthermore, the precursor raw material may include, in addition to the first and second compounds mentioned above, a third compound of gallium and one or more alcohol compounds selected from alcohol compounds. The third compound is, for example, gallium acetylacetonate (Ga(C)). ５ H ７ O ２ ) ３ ) is used as the solvent. ３ OH) is one example.
[0015] Gas supply source 21 supplies carrier gas such as air, nitrogen, or oxygen to the raw material supply container 31 for sending the atomized raw material solution into the reaction vessel 41. Gas supply source 24 supplies dilution gas such as air, nitrogen, or oxygen to the second gas supply pipe P2 for diluting the gas containing the atomized raw material solution. Water 34 for ultrasonic matching is stored in the water storage container 33, and the raw material supply container 31 is positioned inside the water storage container 33 with a portion of it submerged in the water 34 stored in the water storage container 33. An ultrasonic transducer 35 is fixed to the water storage container 33. The ultrasonic waves generated by the ultrasonic transducer 35 are transmitted to the raw material solution 32 stored in the raw material supply container 31 via the matching water 34 stored in the water storage container 33.
[0016] Next, the operation of the mist CVD apparatus will be explained. First, the ultrasonic transducer 35 vibrates, transmitting vibrational energy to the raw material solution 32 via the matching water 34, and this vibrational energy turns the raw material solution 32 into a mist. The misted raw material solution is then sent into the reaction vessel 41 through the second gas supply pipe P2 by carrier gas supplied from the gas supply source 21 into the raw material supply container 31. At this time, the amount of raw material solution sent into the reaction vessel 41 is adjusted by adjusting the flow rate of the carrier gas flowing through the first gas supply pipe P1 while monitoring the flow meter 23. In addition, the concentration of the gas containing the raw material solution sent into the reaction vessel 41 is adjusted by adjusting the flow rate of the dilution gas flowing through the third gas supply pipe P3 while monitoring the flow meter 26. The misted raw material solution sent into the reaction vessel 41 is then supplied to the surface of the substrate W placed in the film deposition chamber S11 of the reaction vessel 41. When the atomized raw material solution supplied to the surface of the substrate W is heated by the heater 42, the metal compounds in the raw material solution and water undergo a chemical reaction, causing metal oxides to grow on the surface of the substrate W. At this point, the substrate W is heated to a temperature within the range of 400°C to 1200°C.
[0017] As described above, in the semiconductor thin film manufacturing method according to this embodiment, Ga ２ O ３ A substrate W formed from crystal contains at least indium and aluminum, and Ga ２ O ３Within the range where the lattice matching degree with the crystal is within the allowable range, (Al ｘ Ga １－ｘ ) ２ O ３ A semiconductor thin film made of a semiconductor crystal having a larger bandgap than the crystal can be formed. Therefore, compared with the semiconductor thin film made of (Al ｘ Ga １－ｘ ) ２ O ３ crystal, the band offset at the interface with the Ga ２ O ３ crystal can be increased. Thus, the design freedom for improving the performance of the semiconductor device by increasing the band offset can be increased accordingly.
[0018] Further, since the mist CVD method employed in the method for manufacturing the semiconductor thin film according to the present embodiment is a method consisting of a non-vacuum process, a configuration for realizing a vacuum atmosphere is unnecessary, and thus the apparatus can be simplified.
[0019] (Embodiment 2) The semiconductor device according to the present embodiment is a so-called high electron mobility transistor (HEMT: High Electron Mobility Transistor). As shown in FIG. 2A, it includes a substrate 101, a first semiconductor crystal layer 102 formed on the substrate 101, and a second semiconductor crystal layer 103 formed on the first semiconductor crystal layer 102. Further, the semiconductor device has n-type dopants that protrude from the second semiconductor crystal layer 103 to the vicinity of the interface of the first semiconductor crystal layer 102 at two locations and are doped at a relatively high concentration compared to other portions of the first semiconductor crystal layer 102, high-doped regions 141 and 142, and electrodes 151, 152, and 153 disposed at two portions corresponding to the two high-doped regions 141 and 142 on the surface of the second semiconductor crystal layer 103 opposite to the first semiconductor crystal layer 102 side and at portions intervening therebetween. The substrate 101 is, for example, a binary metal oxide crystal such as Ga ２ O ３ crystal, Al ２ O ３ crystal, TiO ２ crystal, SiO ２ crystal, or (Alｘ Ga １－ｘ ) ２ O ３ It is formed from a ternary metal oxide composition crystal such as the one shown.
[0020] The first semiconductor crystal layer 102 is made of Ga ２ O ３ It is formed from a crystal. The second semiconductor crystal layer 103 is formed from a semiconductor crystal containing indium and aluminum and contains an n-type dopant. Specifically, the first semiconductor crystal layer 102 is (In ｘ Al １－ｘ ) ２ O ３ It is formed from crystals (0 < x < 1). An example of an n-type dopant is the element Si.
[0021] Si is an example of a doping element included in the highly doped regions 141 and 142. Electrodes 151, 152, and 153 are formed from, for example, a metal, and function as, for example, a source electrode, a drain electrode, and a gate electrode.
[0022] Next, a method for manufacturing a semiconductor device according to this embodiment will be described. First, Ga is placed on a substrate that will serve as the base for the substrate 101. ２ O ３ A first semiconductor crystal layer 102 made of crystals is formed. This first semiconductor crystal layer 102 is formed, for example, by molecular beam epitaxial spectroscopy or CVD.
[0023] Next, a second semiconductor crystal layer 103, consisting of the aforementioned n-type semiconductor crystal containing indium and aluminum, is formed on the first semiconductor crystal layer 102 by the mist CVD method described in Embodiment 1. At this time, indium acetylacetonate (In(C)) described in Embodiment 1 is used as the precursor raw material. ５ H ７ O ２ ) ３ ), aluminum acetylacetone (Al(C) ５ H ７ O ２ ) ３ In addition to the above, we also use a complex ion of Si acetylacetone, which is the basis of the n-type dopant.
[0024] Next, a mask is formed on the side of the second semiconductor crystal layer 103 opposite to the first semiconductor crystal layer 102, covering the portion other than the parts corresponding to the highly doped regions 141 and 142. Then, by irradiating the side of the second semiconductor crystal layer 103 where the mask is formed with Si ions, the highly doped regions 141 and 142 are formed.
[0025] Subsequently, after removing the mask by dry etching or wet etching, a resist mask is formed that covers the portion of the second semiconductor crystal layer 103 opposite to the first semiconductor crystal layer 102, excluding the portion where electrodes 151 and 152 are placed in the area corresponding to the two highly doped regions 141 and 142, and the portion where electrode 153 is placed interposed between the two highly doped regions 141 and 142. Next, a metal film is formed on the surface of the resist mask on the second semiconductor crystal layer 103 by vapor deposition or sputtering, and then electrodes 151, 152, and 153 are formed by a so-called lift-off method, which removes the resist mask by plasma ashing or the like.
[0026] By the way, the second semiconductor crystal layer 103 is made of, for example, (Al ｘ Ga １－ｘ ) ２ O ３ When formed from a crystal (0 < x < 1), as shown in Figure 2B, as the Al composition ratio x approaches 1, the Ga that forms the first semiconductor crystal layer 102 ２ O ３ The degree of lattice mismatch with the crystal increases. Therefore, if the Al composition ratio is increased to enlarge the band gap in the second semiconductor crystal layer 103, defects, cracks, etc. will occur in the second semiconductor crystal layer 103, degrading the quality of the second semiconductor crystal layer 103. For this reason, the band gap of the second semiconductor crystal layer 103 could only be increased by about 0.5 eV compared to the band gap of the first semiconductor crystal layer 102.
[0027] In contrast, in this embodiment, the second semiconductor crystal layer 103 is (In ｘ Al １－ｘ ) ２ O ３By forming it from a crystal (0 < x < 1), the composition ratio x of In is determined by Ga forming the first semiconductor crystal layer 102. ２ O ３ It can be determined to match the crystal and lattice. And the band gap of the second semiconductor crystal layer 103 at this time can be made relatively large, about 1.5 eV, compared to the band gap of the first semiconductor crystal layer 102. For this reason, in the semiconductor device according to this embodiment, the second semiconductor crystal layer 103 is (Al ｘ Ga １－ｘ ) ２ O ３ Compared to semiconductor devices formed from crystals (0 < x < 1), a relatively large band offset can be formed at the interface between the first semiconductor crystal layer 102 and the second semiconductor crystal layer 103. This increases the density of the two-dimensional electron gas, thereby reducing the so-called source-drain resistance when the device is on.
[0028] Furthermore, the semiconductor device of the present invention is not limited to transistors, but may also be an LED (Light Emitting Diode), an LD (Laser Diode), or the like.
[0029] This invention allows for various embodiments and modifications without departing from the broad spirit and scope of the invention. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of the invention. In other words, the scope of the invention is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent meaning of the invention are considered to be within the scope of the invention.
[0030] The method for manufacturing a semiconductor thin film according to the present invention will be described based on examples. However, the present invention is not limited to the examples described below.
[0031] The samples in Examples 1 to 5 are all Ga ２ O ３ The structure has a semiconductor thin film formed on a substrate made of crystal. The substrate used in the samples of Examples 1 to 5 is a Ga substrate with the (010) plane exposed on its surface. ２ O ３ A circuit board was used.
[0032] The semiconductor thin films according to Examples 1 to 5 were formed by the manufacturing method described in Embodiment 1. Here, an ultrasonic transducer vibrating at a frequency of 2.4 MHz (Honda Electronics Co., Ltd., HM-2412) was used as the ultrasonic transducer of the mist CVD apparatus described above. The raw material solutions according to Examples 1 and 2 were In(C) ５ H ７ O ２ ) ３ and Al(C) ５ H ７ O ２ ) ３ And, dissolved CH ３ An OH solution was used. In Example 1, In(C) was used in the raw material solution. ５ H ７ O ２ ) ３ The concentration of Al(C) in the raw material solution is set to 0.04 mol / L. ５ H ７ O ２ ) ３ The concentration was set to 0.10 mol / L. In Example 2, the In(C) in the raw material solution was ５ H ７ O ２ ) ３ The concentration of Al(C) in the raw material solution is set to 0.03 mol / L. ５ H ７ O ２ ) ３ The concentration was set to 0.10 mol / L. In addition, the raw material solutions in Examples 3 to 5 were In(C) ５ H ７ O ２ ) ３ and Al(C) ５ H ７ O ２ ) ３ In addition, Ga(C ５ H ７ O ２ ) ３ CH ３ An OH solution was used. In Examples 3 to 5, In(C) was used in the raw material solution. ５ H ７ O ２ ) ３ The concentration of Al(C) in the raw material solution is set to 0.03 mol / L. ５ H７ O ２ ) ３ The concentration was set to 0.10 mol / L. In Example 3, the Ga(C) in the raw material solution was ５ H ７ O ２ ) ３ The concentration was set to 0.01 mol / L, and in Example 4, Ga(C) in the raw material solution ５ H ７ O ２ ) ３ The concentration was set to 0.02 mol / L, and in Example 5, Ga(C) in the raw material solution ５ H ７ O ２ ) ３ The concentration was set to 0.03 mol / L. Nitrogen was used as the carrier gas and diluent gas. The flow rate of the carrier gas during film formation was set to 2.5 L / min, and the flow rate of the diluent gas was set to 4.5 L / min. During the film formation of the semiconductor thin films according to Examples 1 to 5, the substrate W was placed in the film formation chamber S11 and then heated to 750°C by the heater 42, and the film formation time for Examples 1 to 5 was set to 25 min in all cases.
[0033] Furthermore, for each sample according to Examples 1 to 5, the degree of lattice matching between the semiconductor thin film and the substrate, the morphology and roughness of the semiconductor thin film surface, and the film quality of the semiconductor thin film were evaluated. The crystal structure of the semiconductor thin films according to Examples 1 to 5 was confirmed by the position of the diffraction peak measured using an X-ray diffraction (XRD) measuring device (BRUKER, D8 DISCOVER). The morphology and roughness of the semiconductor thin films according to Examples 1 to 5 were observed using AFM (atomic force microscopy) (SII Nano Technology, Nanonavi / E-sweep). In addition, the film quality of the semiconductor thin films according to Examples 1 to 5 was evaluated using a transmission electron microscope (TEM).
[0034] The results of the evaluations performed on the samples according to Examples 1 to 5 will be described in detail below. As shown in Figure 3A, according to the XRD results of the sample according to Example 1, the β-Ga that forms the substrate ２ O３ Peaks originating from the 020 plane of the crystal and (In ｘ Al １－ｘ ) ２ O ３ A peak originating from the 020 plane of the crystal (0 < x < 1) was observed at approximately the same position. Furthermore, as shown in Figure 3B, in the reciprocal lattice map, the β-Ga forming the substrate was also observed. ２ O ３ The distribution region of reciprocal lattice points corresponding to the crystal, and the β-(In) forming the semiconductor thin film. ｘ Al １－ｘ ) ２ O ３ It can be confirmed that the distribution region of reciprocal lattice points corresponding to the crystal and the region roughly overlap. From this, it can be seen that in Example 1, β-Ga ２ O ３ On a substrate formed from crystals, β-(In ｘ Al １－ｘ ) ２ O ３ It was found that the semiconductor thin film formed from the crystal was formed with a high degree of lattice matching. Furthermore, as shown in Figure 4, the surface of the semiconductor thin film sample according to Example 1 was relatively flat, and the RMS of the semiconductor thin film surface was 0.4 nm. From this, it can be seen that the semiconductor thin film is a high-quality film with a relatively flat surface and almost no defects or cracks observed.
[0035] Furthermore, the atomic-level structure was confirmed for the portion enclosed by rectangular frame 1 in the cross-section of the sample according to Example 1 shown in Figure 5A, and for the portions enclosed by rectangular frames 2-1, 2-2, and 3 shown in Figure 5B. Here, the portion enclosed by rectangular frame 2-1 is a relatively near-surface portion of the semiconductor thin film, the portion enclosed by rectangular frame 2-2 is approximately the central portion in the thickness direction of the semiconductor thin film, and the portion enclosed by rectangular frame 3 is the boundary portion between the semiconductor thin film and the substrate. In the portion enclosed by rectangular frame 2-1 in Figure 5B, as shown in Figures 6A and 6B, a structure in which atoms are regularly arranged and there are almost no defects was observed. Similarly, in the portion enclosed by rectangular frame 2-2 in Figure 5B, as shown in Figures 7A and 7B, a structure in which atoms are regularly arranged and there are almost no defects was observed. Furthermore, even at the boundary between the semiconductor thin film and the substrate enclosed by the rectangular frame 3 in Figure 5B, as shown in Figures 8A and 8B, the atoms were arranged regularly without any disorder at the boundary between the semiconductor thin film and the substrate, and a structure with almost no defects was observed.
[0036] Furthermore, the electron diffraction pattern in the relatively near-surface portion of the semiconductor thin film sample according to Example 1 shows a pattern of high single crystallinity, as shown in Figure 9A. The electron diffraction pattern at the boundary between the semiconductor thin film and the substrate of the sample according to Example 1 also shows a pattern of high single crystallinity, as shown in Figure 9B. From this, it can be seen that the entire semiconductor thin film of the sample according to Example 1 has high single crystallinity.
[0037] As shown in Figure 10, the XRD results for the sample according to Example 2 showed that, similar to the sample according to Example 1, the β-Ga that forms the substrate... ２ O ３ Peaks originating from the 020 plane of the crystal and (In ｘ Al １－ｘ ) ２ O ３ A peak originating from the 020 plane of the crystal was observed at approximately the same position. Furthermore, the XRD results for the samples of Examples 3 to 5 showed that (In ｘ Al １－ｘ ) ｙ Ga ２ーｙ O ３The peaks originating from the crystals are all from the sample of Example 2 (In ｘ Al １－ｘ ) ２ O ３ It was observed at a lower diffraction angle than the peak originating from the crystal. Furthermore, when comparing the XRD results for the samples of Examples 3 to 5, Ga(C) contained in the raw material solution during the deposition of the semiconductor thin film was observed. ５ H ７ O ２ ) ３ A tendency was observed for the diffraction angle to shift to a lower side as the concentration of was higher. From this, it was found that the Ga(C) contained in the raw material solution during semiconductor thin film deposition is a factor. ５ H ７ O ２ ) ３ It was found that by adjusting the concentration of [the substance], it may be possible to control the degree of lattice matching between the semiconductor thin film and the substrate.
[0038] This application is based on Japanese Patent Application No. 2024-230436, filed on 26 December 2024. The entire specification, claims, and drawings of Japanese Patent Application No. 2024-230436 are incorporated herein by reference.
[0039] The present invention is suitable as a method for manufacturing semiconductor devices such as HEMTs.
[0040] 21, 24: Gas supply source, 22, 25: Flow rate adjustment mechanism, 23, 26: Flow meter, 31: Raw material supply container, 33: Water storage container, 35: Ultrasonic transducer, 41: Reaction vessel, 42: Heater, 101: Substrate, 102: First semiconductor crystal layer, 103: Second semiconductor crystal layer, 141, 142: Highly doped regions, 151, 152, 153: Electrodes, 411: Film deposition section, 412: Storage section, P1: First gas supply pipe, P2: Second gas supply pipe, P3: Third gas supply pipe, P4: Exhaust pipe
Claims
1. Ga ２ O ３ A method for manufacturing a semiconductor thin film, comprising the steps of: preparing a substrate formed from crystals; and forming a semiconductor thin film on the substrate by a mist CVD method, the semiconductor thin film being made of a semiconductor crystal containing indium and aluminum.
2. The method for manufacturing a semiconductor thin film according to claim 1, wherein in the step of forming the semiconductor thin film, a precursor raw material comprising a first compound of indium and one or more alcohol compounds selected from alcohol compounds, and a second compound of aluminum and one or more alcohol compounds selected from alcohol compounds is supplied to the surface of the substrate.
3. The first compound is indium acetylacetonate (In(C ５ H ７ O ２ )) and the second compound is aluminum acetylacetonate (Al(C ３ H ５ O ７ ))), the method for manufacturing a semiconductor thin film according to claim 2. 4. The semiconductor thin film is (In ｘ Al １－ｘ ) ２ O ３ A method for manufacturing a semiconductor thin film according to any one of claims 1 to 3, which is formed from a crystal (0 < x < 1).
5. The method for producing a semiconductor thin film according to claim 2 or 3, wherein the precursor raw material further comprises a third compound of gallium and one or more alcohol compounds selected from alcohol compounds.
6. The third compound is gallium acetylacetonate (Ga(C) ５ H ７ O ２ ) ３ The method for manufacturing a semiconductor thin film according to claim 5.
7. The method for manufacturing a semiconductor thin film according to claim 2 or 3, wherein in the step of forming the semiconductor thin film, the raw material solution obtained by dissolving the precursor raw material in methanol is supplied to the surface of the substrate in an atomized form.
8. Ga on the substrate ２ O ３ A method for manufacturing a semiconductor device, comprising: a step of forming a first semiconductor crystal layer made of crystals; a step of forming a second semiconductor crystal layer made of semiconductor crystals containing indium and aluminum on the first semiconductor crystal layer by a mist CVD method; and a step of forming a highly doped region by implanting Si elements into the second semiconductor crystal layer from the side opposite to the first semiconductor crystal layer.