Semiconductor device, preparation method thereof, and epitaxial wafer

Abstract

The present application relates to the field of semiconductors and discloses a semiconductor device, a method for preparing the same, and an epitaxial wafer. The semiconductor device comprises a substrate and a p-type semiconductor film disposed on the surface of the substrate. The chemical formula of the p-type semiconductor film is β-(M z Rh x Ga 1‑x‑z ) 2y O3, M is a doping metal element, and the acceptor energy level of M is less than or equal to 0.55 eV. The value range of x is 0.125≤x≤0.5, the value range of y is 0.9≤y≤1.1, and the value range of z is 0<z≤0.03. This method can obtain a semiconductor device made of p-type β-Ga2O3 material and improve the performance of the semiconductor device.

Description

Technical Field

[0001] The present application relates to the field of semiconductors, and in particular to a semiconductor device, a method for preparing the same, and an epitaxial wafer. Background Art

[0002] Semiconductor power devices have a wide range of applications in fields such as electric transportation, smart grids, and aerospace. The power characteristics of semiconductor materials are positively correlated with their bandgap, with wide-bandgap semiconductors exhibiting higher critical electric fields. Ultra-widebandgap semiconductor materials can significantly reduce the size of semiconductor power modules such as DC converters and inverters, lower on-resistance, and improve energy conversion efficiency. Gallium oxide, diamond, and aluminum nitride are currently the most researched ultra-widebandgap semiconductor materials. Compared to diamond and aluminum nitride, gallium oxide is favored due to its more mature preparation methods.

[0003] β-Ga2O3 is the most stable crystalline phase among various gallium oxide configurations. Similar to most oxides, the valence band top of β-Ga2O3 is primarily contributed by the 2p orbitals of relatively low-energy, localized oxygen atoms. Its flat dispersion relation indicates a high effective hole mass, corresponding to a low hole mobility. Most experimental studies have shown that the theoretical value of the hole mobility of β-Ga2O3 at room temperature is between 1 and 2 cm. 2 V -1 s -1 The acceptor energy levels are mostly above 1.1 eV. Due to the low hole mobility and high acceptor energy levels, achieving p-type conductivity in β-Ga2O3 is difficult. Due to the lack of p-type conductivity, current β-Ga2O3 semiconductor devices are mostly based on unipolar transport via Schottky junctions and bipolar transport via pn heterojunctions. Schottky junctions often exhibit low potential barriers, and the interface states caused by the lattice mismatch of the pn heterojunction become a significant issue for device reverse leakage, resulting in the withstand voltage characteristics of current β-Ga2O3 power devices significantly below the theoretical limit of the material.

[0004] Compared with β-Ga2O3, the semiconductor material β-(Rh x Ga 1-x ) 2y The electron orbital interaction of O3, Rh and O forms a new valence band top. The energy level of the new valence band top is significantly higher than that of β-Ga2O3, which is expected to solve the p-type doping problem of β-Ga2O3. However, how to achieve the p-type doping of β-(Rh x Ga 1-x ) 2y O3 to obtain semiconductor materials with p-type conductivity has become an important research direction. Summary of the Invention

[0005] The present application discloses a semiconductor device and a preparation method thereof, as well as an epitaxial wafer, to obtain a semiconductor device made of p-type β-Ga2O3 material, thereby improving the performance of the semiconductor device.

[0006] To achieve the above objectives, this application provides the following technical solutions:

[0007] In a first aspect, the present application provides a semiconductor device comprising a substrate and a p-type semiconductor film provided on a surface of the substrate; the chemical formula of the p-type semiconductor film is β-(M z Rh x Ga 1-x-z ) 2y O3, M is a doping metal element, and the acceptor energy level of M is less than or equal to 0.55 eV; wherein: the value range of x is 0.125≤x≤0.5, the value range of y is 0.9≤y≤1.1, and the value range of z is 0<z≤0.03.

[0008] The present application provides a semiconductor device using β-(M z Rh x Ga 1-x-z ) 2y O3 semiconductor film is used as p-type layer by β-(Rh x Ga 1-x ) 2y By adding acceptor doping elements to O3, a wide-gap oxide film β-(M z Rh x Ga 1-x-z ) 2y O3. The room temperature hole mobility of this oxide film can be greater than 2 cm 2 V -1 s -1 , even more than 10 cm 2 V - 1 s -1 , the acceptor energy level can be reduced to below 0.4 eV. z Rh x Ga 1-x-z ) 2y O3 has high hole mobility, high crystal quality, and a thick epitaxial layer. This oxide film can fully utilize the high voltage resistance, low switching losses, and enhanced stability of the pn junction to produce higher-performance power devices. Gallium oxide enhancement-mode field-effect transistors are also easily fabricated based on p-type semiconductor films.

[0009] In one implementation, M is selected from at least one of Li, Na, Mg, and Cu. Using the above elements for doping makes it easier to obtain a hole concentration suitable for power device applications to achieve p-type conductivity.

[0010] In one implementation, the value range of x is 0.25≤x≤0.5. By optimizing the solid solution content of Rh, the hole mobility in the semiconductor material can be further improved.

[0011] In one implementation, the room temperature hole mobility of the p-type semiconductor film is greater than 2 cm 2 V -1 s -1 Furthermore, the room temperature hole mobility of the p-type semiconductor film is greater than 10 cm 2 V -1 s -1 High hole mobility means that holes move faster in semiconductor materials, which can improve the operating speed and efficiency of semiconductor devices.

[0012] In one implementation, the acceptor energy level of the p-type semiconductor film is less than or equal to 0.4 eV. When the acceptor energy level of the p-type semiconductor material is lower than 0.4 eV, a high hole concentration can be generated, thereby improving the p-type conductivity of the semiconductor film.

[0013] In one implementation, the substrate is an n-type substrate, which includes a stacked N + β-Ga2O3 layer and N - β-Ga2O3 layer, the p-type semiconductor film is provided on the N - the surface of the β-Ga2O3 layer;

[0014] A first electrode layer is provided on a surface of the substrate facing away from the p-type semiconductor film, and a second electrode layer is provided on a surface of the p-type semiconductor film facing away from the substrate.

[0015] In one implementation, the substrate is a β-Ga2O3 substrate, and a portion of the surface of the p-type semiconductor film is provided with an n-type layer, and the n-type layer is N + β-Ga2O3 layer, an electrode layer is provided on the surface of the n-type layer away from the p-type semiconductor film.

[0016] In a second aspect, the present application provides a method for preparing a semiconductor device, which forms the p-type semiconductor thin film on the surface of the substrate by using an epitaxial growth process and an ion implantation process.

[0017] In one embodiment, the method of forming the p-type semiconductor thin film using an ion implantation process includes:

[0018] Under vacuum conditions, the β-(Rh x Ga 1-x )2O3 film is implanted with M ions;

[0019] The film after ion implantation is annealed to obtain the p-type semiconductor film.

[0020] In a third aspect, the present application provides an epitaxial wafer comprising a substrate and a p-type semiconductor film disposed on the substrate, wherein the chemical formula of the p-type semiconductor film is β-(M z Rh x Ga 1-x-z ) 2y O3, M is a doping metal element, and the acceptor energy level of M is less than or equal to 0.55 eV; wherein: the value range of x is 0.125≤x≤0.5, the value range of y is 0.9≤y≤1.1, and the value range of z is 0<z≤0.03.

[0021] Among them, the data in the above-mentioned possible implementation methods of the present application, such as the values ​​of x / y / z, the acceptor energy level of the p-type semiconductor material, the room temperature hole mobility and other data, when measured, the values ​​within the engineering measurement error range should be understood to be within the range specified in the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of a diode;

[0023] Figure 2 A schematic diagram of the structure of a horizontal MOSFET device;

[0024] Figure 3 Schematic diagram of the unit cell configuration structure after doping with different metal M;

[0025] Figure 4 Different metal elements M doped β-(Rh 0.25 Ga 0.75 )2O3 and β-(Rh 0.5 Ga 0.5 )2O3 after the acceptor energy level diagram;

[0026] Figure 5 Graphs showing hole mobility tests of the semiconductor films of Examples 1 to 4;

[0027] Figure 6 Graph showing hole mobility in different directions of the semiconductor film of Example 4. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] It should be noted that, unless otherwise specified, all embodiments and preferred implementation methods described herein can be combined to form new technical solutions. Unless otherwise specified, all technical features and preferred features described herein can be combined to form new technical solutions. Unless otherwise specified, percentages (%) or parts refer to mole percentages or mole ratios relative to the composition. Unless otherwise specified, the components or preferred components described herein can be combined to form new technical solutions. Unless otherwise specified, the numerical range "a-b" is an abbreviation for any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6-22" indicates that all real numbers between "6-22" are listed herein, and "6-22" is merely an abbreviation for these numerical combinations. "Range" disclosed herein in the form of lower limits and upper limits can refer to one or more lower limits and one or more upper limits, respectively. Unless otherwise specified, reactions or steps can be performed sequentially or in a sequential order. Preferably, the reaction methods described herein are performed sequentially.

[0030] Unless otherwise indicated, the professional and scientific terms used herein are the same as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to this application.

[0031] High-power semiconductor devices are crucial to the development of technologies such as new energy vehicles and smart grids, improving energy conversion efficiency. The power characteristics of semiconductor devices are positively correlated with the band gap and carrier mobility of the semiconductor material. Gallium oxide, with its ultra-wide band gap (approximately 4.9 eV) and mature synthesis methods, is an ideal material for high-power semiconductor devices. β-Ga2O3 (space group monoclinic C2 / m) has the most stable crystal structure and is suitable for applications in high-temperature, high-voltage, and high-power applications. Current research on gallium oxide is primarily based on this crystal configuration.

[0032] To achieve p-type doping of β-Ga2O3, various improvements are currently available. The following two examples illustrate the performance of existing p-type β-Ga2O3 semiconductor materials. Prior art one utilizes co-doping of two groups of elements: one group is S, Se, and Te, which are members of the same oxygen group; the other is Be, Mg, and Ca, members of Group II. This ion co-doping can produce p-type β-Ga2O3. However, due to the difficulty in controlling the doping process and doping concentration, the resistivity of these doped semiconductor materials is relatively high, typically around 5731 Ω·cm, making it difficult to achieve a low-resistance p-type semiconductor.

[0033] In the second prior art, a low-resistivity p-type semiconductor material can be obtained by co-doping β-Ga2O3 with N and Al. However, the hole mobility of the p-type semiconductor in the above solution is low.

[0034] Based on the above problems, an embodiment of the present application provides a semiconductor device. Figure 1 A schematic diagram of the structure of a diode. Figure 2 This is a schematic diagram of the structure of a horizontal MOSFET device. Figure 1 and Figure 2 As shown, the semiconductor device includes a substrate 10 and a p-type semiconductor film 20 provided on the surface of the substrate. The substrate can be an n-type substrate or a p-type substrate.

[0035] In the semiconductor device of the embodiment of the present application, the chemical formula of the p-type semiconductor film 20 is β-(M z Rh x Ga 1-x-z ) 2y O3, M is a doping metal element, and the acceptor energy level of M is less than or equal to 0.55 eV; wherein: the value range of x is 0.125≤x≤0.5, the value range of y is 0.9≤y≤1.1, and the value range of z is 0<z≤0.03.

[0036] The p-type semiconductor film in the semiconductor device of the embodiment of the present application utilizes the doping metal element M with an acceptor energy level less than or equal to 0.55 eV to form a solid solution type β-(Rh x Ga 1-x ) 2y O3 doping can obtain a semiconductor film β-(M z Rh x Ga 1-x-z ) 2y O3 is beneficial for obtaining semiconductor devices with high response performance.

[0037] The p-type semiconductor film in the embodiment of the present application has a chemical formula of β-(Mz Rh x Ga 1-x-z ) 2y O3. Wherein, M is an acceptor-type doping metal element, and the acceptor energy level of M is less than or equal to 0.55 eV. The chemical formula is β-(M z Rh x Ga 1-x-z ) 2y In O3, x, y, and z represent atomic percentages. The value range of x is 0.125 ≤ x ≤ 0.5, the value range of y is 0.9 ≤ y ≤ 1.1, and the value range of z is 0 < z ≤ 0.03. For example, x can be 0.125, 0.1875, 0.25, 0.3125, 0.375, 0.4375, 0.5, or any value between the above two values. y can be 0.9, 0.92, 0.94, 0.96, 0.98, 1, 1.02, 1.04, 1.06, 1.08, 1.1, or any value between the above two values. z may be 0.001, 0.003, 0.005, 0.008, 0.01, 0.012, 0.015, 0.018, 0.02, 0.022, 0.025, 0.028, or 0.03 or any value between any two of the above values.

[0038] The p-type semiconductor thin film in this application is a non-stoichiometric compound, where y represents the non-stoichiometric ratio of the metal element to oxygen. A non-stoichiometric compound (also known as a non-stoichiometric compound) is one whose atomic ratios are not simple integer ratios, and whose composition varies within a certain range, not conforming to the law of definite composition. These compounds are essentially substitutional solid solutions between high-valent and low-valent ions of the same element, or whose composition deviates from ideal stoichiometry due to lattice defects (such as vacancies and interstitial atoms).

[0039] The p-type semiconductor film of the embodiment of the present application is β-(Rh x Ga 1-x ) 2y Based on O3 solid solution material, by doping the acceptor element M, p-type conductive function can be achieved, and the band gap can reach 4.10 eV. At the same time, it has a high hole mobility, which is conducive to obtaining semiconductor devices with high response performance.

[0040] In one embodiment, the M is selected from at least one of Li, Na, Mg, and Cu. Using the above elements for doping makes it easier to obtain a hole concentration suitable for power device applications to achieve p-type conductivity.

[0041] In one embodiment, the value range of x is 0.25≤x≤0.5. By optimizing the solid solution content of Rh, the hole mobility in the semiconductor material can be further improved.

[0042] The p-type semiconductor film of the embodiment of the present application has a room temperature hole mobility greater than 2 cm 2 V -1 s -1 Furthermore, the room temperature hole mobility of the p-type semiconductor film can be greater than 10 cm 2 V -1 s -1 , for example, it can be greater than 10 cm 2 V -1 s -1 In one embodiment, the room temperature hole mobility of the p-type semiconductor film is 2-20 cm 2 V -1 s -1 Furthermore, the p-type semiconductor film of the present invention can exhibit significant anisotropy. High hole mobility means that holes move faster in the semiconductor material, which can directly improve the operating speed and efficiency of semiconductor devices.

[0043] In addition, the acceptor energy level of the p-type semiconductor film of the embodiment of the present application is less than or equal to 0.4 eV. The conductivity of a p-type semiconductor material is proportional to the excited hole concentration and hole mobility. When the acceptor energy level of the p-type semiconductor material is less than 0.4 eV, a high hole concentration can be excited, thereby improving the p-type conductivity of the semiconductor film.

[0044] The β-(M z Rh x Ga 1-x-z ) 2y O3 semiconductor thin film, through the β-(Rh x Ga 1-x ) 2y By adding acceptor doping elements to O3, a wide-gap oxide film β-(M z Rh x Ga 1-x-z ) 2y O3. The room temperature hole mobility of this oxide film can be greater than 2 cm 2 V -1 s -1 , even more than 10 cm 2 V -1 s -1 , the acceptor energy level can be reduced to below 0.4eV. z Rh x Ga 1-x-z ) 2yO3 has high hole mobility, high crystal quality, and a thick epitaxial layer. This oxide film can fully utilize the high voltage resistance, low switching losses, and enhanced stability of the pn junction to produce higher-performance power devices. Gallium oxide enhancement-mode field-effect transistors are also easily fabricated based on p-type semiconductor films.

[0045] The preparation method of the p-type semiconductor thin film of the embodiment of the present application includes but is not limited to ion implantation, diffusion implantation or epitaxial growth, etc. The preparation method of the p-type semiconductor thin film of the embodiment of the present application is described below using ion implantation as an example.

[0046] The method of performing p-type doping by ion implantation includes the following steps:

[0047] S1. Surface cleaning: β-(Rh x Ga 1-x )2O3 film is surface cleaned. For example, acetone, isopropyl alcohol, and deionized water are used to clean the surface in sequence, and finally the surface is blown dry with N2 to obtain a clean surface.

[0048] S2, ion implantation: β-(Rh x Ga 1-x )2O3 film sample was placed in the ion implantation equipment, and the sample chamber was evacuated to a vacuum degree of 1x10 -4 Pa and below to ensure stable vacuum. Set the accelerating voltage to focus the ion beam, the ion injection energy range is 50~200 kV, and the injection dose is selected as 10 15 ~10 17 ions / cm 2 , adjust the sample β-(Rh x Ga 1-x )2O3 film position for M ion implantation.

[0049] S3. Post-implantation annealing: The ion-implanted film sample is placed in a vacuum annealing furnace at a temperature between 500°C and 800°C for 5 minutes. Annealing repairs lattice damage caused by the ion implantation process and simultaneously activates acceptor impurities. Activating acceptor impurities excites electrons at the top of the valence band to acceptor levels, resulting in a high hole concentration. After acceptor impurity doping, isolated acceptor levels appear above the top of the valence band in the semiconductor band diagram. Under high temperature or light excitation, electrons at the top of the valence band jump to slightly higher acceptor levels, leaving holes at the top of the valence band. Under the action of an electric field, the movement of holes at the top of the valence band generates an electric current.

[0050] The performance of the p-type semiconductor material of the embodiment of the present application will be specifically explained below with reference to specific embodiments.

[0051] Examples 1 to 4

[0052] Examples 1 to 4 are semiconductor films, respectively, and their molecular formulas are β-(M z Rh 0.125 Ga 0.875-z )2O3、β-(M z Rh 0.25 Ga 0.75-z )2O3、β-(M z Rh 0.375 Ga 0.625-z )2O3、β-(M z Rh 0.5 Ga 0.5-z In Examples 1 to 4, the doping element M is the same and the value of z is the same.

[0053] Since the hole concentration is closely related to the acceptor energy level, the following is based on the β-(Rh 0.25 Ga 0.75 )2O3 and β-(Rh 0.5 Ga 0.5 )2O3 is used as the basic material to test the changes in the acceptor energy levels of semiconductor films doped with different acceptor doping elements M.

[0054] Figure 3 Schematic diagram of the unit cell structure after doping with different metal M. Figure 3 As shown, for the β-(Rh x Ga 1-x ) 2y For O3, there are two unequal Ga atoms in the unit cell, one located at the center of the octahedron formed by oxygen atoms, and the other located at the center of the tetrahedron formed by oxygen atoms.

[0055] Figure 3 In (a), a metal atom M replaces β-(Rh 0.25 Ga 0.75 )2O3 oxygen octahedron center Ga atom doping configuration, marked as M Ga-I .

[0056] Figure 3 In (b), a metal atom M replaces β-(Rh 0.25 Ga 0.75 )2O3 oxygen tetrahedron center Ga atom doping configuration, marked as M Ga-II .

[0057] Figure 3 In (c), a metal atom M replaces β-(Rh 0.5 Ga 0.5 )2O3 oxygen tetrahedron center Ga atom doping configuration, marked as M Ga-II .

[0058] like Figure 3 As shown, β-(Rh 0.25 Ga 0.75 )2O3 has two kinds of Ga atomic sites, corresponding to M Ga-I and M Ga-II Two doping configurations. β-(Rh 0.5 Ga 0.5 )2O3 Ga-I atomic sites are all occupied by Rh atoms, corresponding to the existence of a doping configuration M that replaces the Ga site. Ga-II The corresponding Ga vacancy configuration is marked as Vac Ga-I and Vac Ga-II .

[0059] The doping metal elements M include Li, Na, and K from Group 1 of the periodic table, Be, Mg, and Ca from Group 2, Cu, Ag, and Au from Group 11, and Zn, Cd, and Hg from Group 12, as well as Ga vacancies.

[0060] Figure 4 Different metal elements M doped β-(Rh 0.25 Ga 0.75 )2O3 and β-(Rh 0.5 Ga 0.5 )2O3 after the acceptor energy level diagram. Figure 4 As shown in , the acceptor energy level of the semiconductor film obtained by doping is significantly lower than the numerical value. Figure 4 As shown in (a), in β-(Rh 0.25 Ga 0.75 )2O3, the acceptor energy level of Mg doping is 0.824 eV, which is significantly lower than its 1.1 eV in β-Ga2O3. In particular, when Li, Na and Cu replace Ga-I atoms, the doping energy levels are 0.388 eV, 0.381 eV and 0.395 eV, respectively, which are significantly lower than the acceptor energy levels of other doping elements. This shows that the acceptor energy levels of Li, Na and Cu doping β-(Rh 0.25 Ga 0.75 )2O3 is easier to obtain hole concentration and p-type conductivity suitable for power device applications.

[0061] Different doping elements in β-(Rh 0.5 Ga 0.5 )2O3 in the acceptor level such as Figure 4As shown in (b), the Mg-doped Ga-II site presents the lowest acceptor energy level, which is 0.543 eV, indicating that the Mg-doped β-(Rh 0.5 Ga 0.5 )2O3 is also easy to obtain a suitable hole concentration. Therefore, Li, Na, Mg and Cu can be selected as β-(Rh x Ga 1-x )2O3 structure acceptor doping impurity elements. Figure 5 Graphs showing the hole mobility tests of the semiconductor films of Examples 1 to 4. Figure 5 In the equation, the horizontal axis is the hole concentration and the vertical axis is the mobility. Figure 5 As shown in Figure 1, when the atomic ratio of Rh is above 0.25, the hole mobility of the corresponding semiconductor film is higher. 17 cm -3 Under the hole concentration, β-(M z Rh x Ga 1-x-z )2O3 (x = 0.250 and 0.500) corresponding to room temperature hole mobility of 7.00 cm 2 V -1 s -1 and 10.7 cm 2 V -1 s -1 In the lower 10 16 cm -3 Under the hole concentration, β-(M z Rh 0.5 Ga 0.5-z )2O3 has a room temperature hole mobility of 12.4 cm 2 V -1 s -1 The above values ​​are significantly higher than β-(M z Ga 1-z )2O3 hole mobility, indicating that the β-(Rh x Ga 1-x )2O3 makes it easy to obtain p-type conductive semiconductor films with better performance.

[0062] Figure 6 Graphs showing hole mobility in different directions of the semiconductor film of Example 4. Figure 6 As shown in Figure 2, the hole mobility of semiconductor materials has significant anisotropy. Among them, the hole mobility in the x-axis direction has a significant dependence on the concentration of Rh. Figure 6 As shown, the embodiment β-(M z Rh 0.5 Ga 0.5-z )2O3 in 10 17 cm -3At a hole concentration of 1.57 nm, the hole mobility along the x-axis can reach 16.6 cm 2 V -1 s -1 Based on its significant anisotropy and high hole mobility in the x-axis, the carrier migration direction can be set along the x-axis during the device preparation process to improve the device's response performance.

[0063] In addition, the p-type semiconductor film of the embodiment of the present application has a band gap of 4.10 eV, which can meet the requirements of ultra-wide band gap semiconductor power devices. The room temperature hole mobility of the p-type semiconductor film can exceed 10 cm 2 V -1 s -1 , making it easy to obtain devices with lower conductive resistance and faster response performance. In addition, the p-type semiconductor film of the embodiment of the present application can be p-type doped using a single ion implantation method, which can obtain a thick film while reducing damage to the crystal lattice. During the preparation process, there is no phase transition process in the crystal lattice, which can produce a film with higher crystal quality.

[0064] Reference Figure 1 , based on p-type β-(M z Rh x Ga 1-x-z ) 2y The structure of the pn junction diode prepared by O3 thin film, in the n-type heavily doped N + A layer of n-type lightly doped N is epitaxially grown on the surface of the β-Ga2O3 layer 101. - The epitaxial layer of the β-Ga2O layer 102 is then formed on the p-type semiconductor film 20 by epitaxy and ion implantation processes, i.e., β-(M z Rh x Ga 1-x-z ) 2y O3 thin film layer, and finally ohmic electrodes are plated on both sides. The ohmic electrode provided on the surface of the substrate 10 facing away from the p-type semiconductor film 20 is the first electrode layer 31, and the ohmic electrode provided on the surface of the p-type semiconductor film 20 facing away from the substrate 10 is the second electrode layer 32.

[0065] Among them, since β-Ga2O3 lacks p-type conductivity, it is difficult to form a pn homojunction. Existing reports are mostly based on the Schottky junction of β-Ga2O3 and metal or the use of n-type β-Ga2O3 and p-type NiO and other materials to form a pn heterojunction. The pn junction in the semiconductor device of the embodiment of the present application has advantages such as lower reverse leakage, higher breakdown voltage and better temperature stability compared to the Schottky junction, and is more suitable for the application of high-power devices. Compared with the reported p-type NiO and other pn heterojunction structures, the present application adopts p-type β-(M z Rh x Ga1-x-z ) 2y The O3 thin film layer replacing the p-type NiO layer has the following advantages: β-(M z Rh 0.5 Ga 0.5-z )2O3 has the same monoclinic crystal symmetry as β-Ga2O3, and its lattice parameters are very close to those of β-Ga2O3. z Rh 0.5 Ga 0.5-z ) 2y In O3, the lattice parameters on the a, b, and c axes are only 0.6%, 2.8%, and 0.8% higher than those of β-Ga2O3. The commonly used p-type NiO material has a cubic structure and the lattice mismatch with β-Ga2O3 is more than 30%. This application adopts β-(M z Rh x Ga 1-x-z ) 2y O3, as the p-type layer of the pn junction, can significantly reduce the interface state caused by lattice mismatch, reduce the reverse leakage current caused by the interface state, and improve the switching ratio and voltage resistance characteristics of the pn junction.

[0066] Reference Figure 2 , based on p-type β-(M z Rh x Ga 1-x-z ) 2y Schematic diagram of the horizontal MOSFET device structure prepared by O3 thin film, using p-type β-(M z Rh x Ga 1-x-z ) 2y The horizontal MOSFET structure of O3 thin film is formed by epitaxy and ion implantation on the semi-insulating β-Ga2O3 substrate 10. z Rh x Ga 1-x-z ) 2y O3 p-type semiconductor film 20, depositing gate oxide, selective etching, epitaxial growth at both ends and ion implantation to form n-type heavily doped N + β-Ga2O3 layer 101, deposit source 41, drain 42, anneal to achieve ohmic contact, and then deposit gate 43. Similar to pn junction diode, p-type β-(M z Rh x Ga 1-x-z ) 2y The MOSFET structure of the O3 thin film has advantages such as high voltage resistance. In addition, the enhancement mode device prepared based on this p-type layer has advantages such as higher safety and lower static power consumption.

[0067] In addition, based on the p-type β-(M zRh x Ga 1-x-z ) 2y The semiconductor device prepared by O3 thin film is not limited to the above embodiment. For example, based on the p-type β-(M z Rh x Ga 1-x-z ) 2y Vertical MOSFET, junction barrier Schottky diode prepared by O3 thin film, and β-(M z Rh x Ga 1-x-z ) 2y The pn homojunction diode and field effect transistor devices realized by O3 thin film are also protected by this application.

[0068] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations.

Claims

1. A semiconductor device, characterized in that: It comprises a substrate and a p-type semiconductor film provided on the surface of the substrate; The chemical formula of the p-type semiconductor film is β-(M z Rh x Ga 1-x-z ) 2y O3, wherein M is a doping metal element, and the acceptor energy level of M is less than or equal to 0.55 eV; Among them: the value range of x is 0.125≤x≤0.5, the value range of y is 0.9≤y≤1.1, and the value range of z is 0 <z≤0.03。 2. The semiconductor device according to claim 1, wherein The M is selected from at least one of Li, Na, Mg, and Cu.

3. The semiconductor device according to claim 1 or 2, wherein: The value range of x is 0.25≤x≤0.

5.

4. The semiconductor device according to claim 1 or 2, wherein: The room temperature hole mobility of the p-type semiconductor film is greater than 2 cm 2 V -1 s -1 .

5. The semiconductor device according to claim 1 or 2, wherein: The acceptor energy level of the p-type semiconductor film is less than or equal to 0.4 eV.

6. The semiconductor device according to claim 1 or 2, wherein: The substrate is an n-type substrate, and the n-type substrate includes a stacked N + β-Ga2O3 layer and N - β-Ga2O3 layer, the p-type semiconductor film is provided on the N - the surface of the β-Ga2O3 layer; A first electrode layer is provided on a surface of the substrate facing away from the p-type semiconductor film, and a second electrode layer is provided on a surface of the p-type semiconductor film facing away from the substrate.

7. The semiconductor device according to claim 1 or 2, wherein: The substrate is a β-Ga2O3 substrate, and a portion of the surface of the p-type semiconductor film is provided with an n-type layer. + β-Ga2O3 layer, an electrode layer is provided on the surface of the n-type layer away from the p-type semiconductor film.

8. The method for preparing a semiconductor device according to any one of claims 1 to 7, wherein: The p-type semiconductor thin film is formed on the surface of the substrate by using an epitaxial growth process and an ion implantation process.

9. The preparation method according to claim 8, characterized in that The method of forming the p-type semiconductor thin film by using an ion implantation process includes: Under vacuum conditions, the β-(Rh x Ga 1-x )2O3 film is implanted with M ions; The film after ion implantation is annealed to obtain the p-type semiconductor film.

10. An epitaxial wafer, characterized in that: It includes a substrate and a p-type semiconductor film provided on the substrate, wherein the chemical formula of the p-type semiconductor film is β-(M z Rh x Ga 1-x-z ) 2y O3, wherein M is a doping metal element, and the acceptor energy level of M is less than or equal to 0.55 eV; Among them: the value range of x is 0.125≤x≤0.5, the value range of y is 0.9≤y≤1.1, and the value range of z is 0<z≤0.03.

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