Ion implantation co-doping method for high-aluminum-component nitride with high hole concentration

Abstract

The invention discloses a high-hole-concentration high-aluminum-component nitride ion implantation co-doping method, and relates to the technical field of semiconductor device preparation technologies, and the method comprises the steps: preparing a semiconductor device which comprises a high-aluminum-component nitride layer; performing ion implantation on the high-aluminum component nitride layer to form a p-type doped high-aluminum component nitride layer; according to the ion implantation, first impurity atoms and second impurity atoms are implanted into the high-aluminum component nitride layer; the first impurity atoms are used for forming p-type doping in the high-aluminum component nitride layer; the second impurity atoms are at least used for reducing formation energy and activation energy of the first impurity atoms in the high-aluminum component nitride layer. According to the technical scheme, by means of co-doping the impurity atoms and the second impurity atoms, the formation energy and the activation energy of the first impurity atoms serving as acceptor atoms can be effectively reduced, the stability and the activation rate of the first impurity atoms in the high-aluminum component nitride layer can be improved, and therefore the hole concentration after doping can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor device preparation technology, and in particular to a method for co-doping nitride ions with high hole concentration and high aluminum component by implantation. Background Art

[0002] With the advent of the information age, the demand for high-frequency and high-power optoelectronic devices is increasing, and the third-generation wide bandgap semiconductor materials (bandgap width of 2.3eV and above) represented by GaN and SiC have emerged. Compared with the first two generations of semiconductor materials, the third-generation semiconductor materials have the advantages of large bandgap width, high thermal conductivity, large breakdown voltage and electron drift rate, and are widely used in high-temperature power devices, high-frequency microwave devices and light-emitting diodes. As a direct bandgap semiconductor material, AlN has a bandgap width of up to 6.2eV, so it is also called an ultra-wide bandgap semiconductor. Since the larger the energy gap of a semiconductor optoelectronic device, the shorter its emission wavelength. Therefore, the emission wavelength of AlN can theoretically be as low as 200nm, which is located in the deep ultraviolet band. AlN can also form a multi-compound semiconductor with InN, GaN, etc. to change the bandgap width, thereby realizing the continuous adjustable emission wavelength from 210nm to 1800nm. It is an ideal material for preparing light-emitting devices and has become an indispensable material in the fields of lighting, display, solid-state lasers, etc.

[0003] As optoelectronic devices in the visible region gradually mature, people gradually turn their attention to the ultraviolet and deep ultraviolet fields with shorter wavelengths. For example, high-aluminum AlGaN can be used to prepare deep ultraviolet light-emitting diodes with a wavelength below 300nm, which can replace the existing mercury-containing ultraviolet light source and be effectively used in the disinfection and sterilization of air, water, and surfaces in various occasions; AlGaN-based ultraviolet lasers have high beam quality, high power density, and high modulation speed due to their unique spatiotemporal coherence characteristics, and are suitable for laser processing, data storage, nano-graphic lithography, disinfection and other fields; the ultraviolet band in sunlight is absorbed by the earth's ozone layer, so the ultraviolet noise on the earth's surface is low. The ultra-wide band gap of high-aluminum AlGaN-based detectors can inhibit the absorption of visible light, which can overcome the limitations of many Si-based detection technologies and improve the performance and reliability of detectors. At present, in order to produce these devices, n-type and p-type dopants are usually introduced during the epitaxial growth process of MOCVD (metal organic chemical vapor deposition) to achieve doping of high Al component nitrides.

[0004] In the prior art, it is still difficult to achieve high-concentration p-type doping in high-aluminum component nitrides. This is because the formation energy and activation energy of the doping atoms currently used to achieve p-type doping in the doped high-aluminum component nitride are relatively large, and as the Al element component increases, its formation energy and activation energy will further increase, and the process of achieving high hole concentration p-type doping in high-aluminum component nitrides is relatively difficult. Summary of the invention

[0005] In view of the above problems, the present application provides a high hole concentration high aluminum component nitride ion implantation co-doping method, which can achieve high hole concentration p-type doping in high aluminum component nitride. The specific scheme is as follows: A high hole concentration high aluminum component nitride ion implantation co-doping method comprising: preparing a semiconductor device, the semiconductor device comprising a high aluminum component nitride layer; Ion implantation is performed on the high aluminum component nitride layer to form a p-type doped high aluminum component nitride layer; Among them, ion implantation implants the first impurity atoms and the second impurity atoms into the high-aluminum component nitride layer; the first impurity atoms are used to form p-type doping in the high-aluminum component nitride layer; the second impurity atoms are at least used to reduce the formation energy and activation energy of the first impurity atoms in the high-aluminum component nitride layer.

[0006] Optionally, in the above-mentioned high-hole-concentration high-aluminum component nitride ion implantation co-doping method, after the ion implantation is completed, the hole concentration in the high-aluminum component nitride layer is not less than 10 18 cm -3 .

[0007] Optionally, in the above-mentioned high-hole-concentration high-aluminum component nitride ion implantation co-doping method, in the high-aluminum component nitride layer, the content of the Al element ranges from 0.7 to 1.0, including the endpoint values.

[0008] Optionally, in the above-mentioned high-hole-concentration high-aluminum component nitride ion implantation co-doping method, the high-aluminum component nitride layer includes: Al x Ga 1-x N or Al x In 1-x N; Wherein, x is the content of Al element.

[0009] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, the first impurity atoms include at least one of Mg atoms and / or Be atoms.

[0010] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, the second impurity atom and the Al atom have the same valence electrons.

[0011] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, the second impurity atoms include B atoms.

[0012] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, it also includes: After the ion implantation is completed, a high temperature annealing process is performed to repair implantation-induced damage and activate the p-type doping.

[0013] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, the method of performing high temperature annealing treatment includes: The semiconductor device is placed in a N 2 In an environment above 1000°C.

[0014] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, during ion implantation, the ion energy of the first impurity atom is 5KeV~100KeV, including the endpoint values; the ion energy of the second impurity atom is 5KeV~100KeV, including the endpoint values.

[0015] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, the mass-to-charge ratio of the first impurity atom is A 1 , the mass-to-charge ratio of the second impurity atom is A 2 , the ion implantation energy of the first impurity atom is E 1 , the ion implantation energy of the second impurity atom is E 2 ; During ion implantation, the ion implantation energies of the first impurity atom and the second impurity atom satisfy: ; Where C is a constant.

[0016] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, when the ion implantation is performed, the ion implantation dose of the first impurity atom is 10 13 cm -3 ~10 16 cm -3 The ion implantation dose of the second impurity atom is 10 13 cm -3 ~10 16 cm -3 .

[0017] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, when performing ion implantation, the ion implantation dose of the first impurity atom and the ion implantation dose of the second impurity atom are the same.

[0018] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, when the ion implantation is performed, the ion implantation angle is 7°.

[0019] Optionally, during ion implantation, after first impurity atoms are implanted into the high-aluminum component nitride layer, second impurity atoms are implanted into the high-aluminum component nitride layer; Alternatively, during ion implantation, the second impurity atoms are implanted into the high-aluminum component nitride layer, and then the first impurity atoms are implanted into the high-aluminum component nitride layer.

[0020] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, when the ion implantation is performed, the ion implantation temperature is 500° C. to 1000° C., including the end value.

[0021] Optionally, in the above-mentioned high hole concentration high aluminum component nitride ion implantation co-doping method, the semiconductor device is an ultraviolet photoelectric device; the semiconductor device also includes an n-type semiconductor layer; The p-type doped high aluminum component nitride layer serves as a p-type semiconductor layer and forms a pn junction of an ultraviolet photoelectric device with an n-type semiconductor layer.

[0022] By means of the above-mentioned technical scheme, in the high-hole-concentration high-aluminum component nitride ion implantation co-doping method provided in the present application, when ion implantation is performed in the high-aluminum component nitride layer of a semiconductor device, the first impurity atom and the second impurity atom are co-doped to inject the first impurity atom and the second impurity atom into the high-aluminum component nitride layer, and the first impurity atom can form p-type doping in the high-aluminum component nitride layer, and the second impurity atom can reduce the formation energy and activation energy of the first impurity atom in the high-aluminum component nitride layer.

[0023] The present application can use the first impurity atom as a p-type dopant to achieve p-type doping of the high-aluminum component nitride layer, and can also use the second impurity atom to make the first impurity atom have a lower formation energy and activation energy, thereby improving the stability and activation rate of the first impurity atom in the high-aluminum component nitride layer, thereby increasing the hole concentration after doping, and preparing a p-type doped high-aluminum component nitride with a high hole concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0025] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0026] Figure 1 A schematic diagram of a process for a high hole concentration high aluminum component nitride ion implantation co-doping method provided in an embodiment of the present application; Figure 2 A schematic flow chart of another high hole concentration high aluminum component nitride ion implantation co-doping method provided in an embodiment of the present application; Figure 3 A cross-sectional view of a GaN-based UV-LED; Figure 4-Figure 6 For Figure 3 The schematic diagram of the principle of p-type doping of a high aluminum component nitride layer in a GaN-based UV-LED is shown; Figure 7 Schematic diagram of the 3×3×3 supercell structure of AlN after p-doping; Figure 8 After p-doping, Al 0.75 Ga 0.25 Schematic diagram of the 2×2×2 supercell structure of N; Fig. 9 is a curve diagram showing the relationship between the impurity formation energy and the Al chemical potential in p-type doped AlN; Fig.10 is a bar graph of activation energy of impurities in p-type doped AlN; Fig.11 The bar graph is a graph of the formation energy when Mg atoms are doped alone and co-doped with B atoms in AlN materials with different doping concentrations in a N-rich environment; Fig.12 The bar graphs are of the formation energy when Be atoms are doped alone and co-doped with B atoms in AlN materials with different doping concentrations in N-rich environments; Fig.13 P-type doped Al 0.75 Ga 0.25 The relationship between the impurity formation energy in N and the chemical potential of Al; Fig.14 P-type doped Al 0.75 Ga 0.25 Histogram of activation energy of impurities in N; Fig.15 This is the energy band structure diagram when Mg atoms are doped alone in AlN material; Fig.16 This is the energy band structure diagram when Mg atoms and B atoms are co-doped in AlN material; Fig.17 This is the energy band structure diagram when Be atoms are doped alone in AlN material; Fig.18 This is the energy band structure diagram when Be atoms and B atoms are co-doped in AlN material.

[0027] Reference numerals: 101 - substrate; 102 - buffer layer; 103 - superlattice layer; 104 - n-type semiconductor layer; 105 - multi-quantum well layer; 106 - electron blocking layer; 107 - hole injection layer; 108 - contact layer. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the embodiments of the present application. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0029] As described in the background technology, it is still difficult to achieve high-concentration p-type doping in high-aluminum component nitrides. The higher the Al content in the high-aluminum component nitrides, the higher the formation energy and activation energy of the p-type doping atoms in the high-aluminum component nitrides, which makes doping more difficult.

[0030] Taking UV-LED, one of the research hotspots in the field of optoelectronic devices, as an example, the doping of n-type semiconductor layer in UV-LED can easily achieve high electron concentration through Si source substitution. However, it is still difficult to achieve high concentration of p-type doping in p-type semiconductor layer in UV-LED. In UV-LED, both n-type semiconductor layer and p-type semiconductor layer are AlGaN materials.

[0031] At present, Mg and Be are two commonly used p-type dopants. However, the solid solubility of Mg and Be in nitrides is limited and the activation energy is large. In particular, as the Al component in AlGaN increases, the formation energy and activation energy of the p-type dopant will further increase, making the preparation of high-aluminum AlGaN materials with high hole concentration extremely challenging.

[0032] Taking Mg as a p-type dopant as an example, experimental results show that the activation energy of Mg in AlN is around 500meV. The ratio of hole carriers to impurity concentrations is: Among them, e is a natural constant, E A is the activation energy, is the Boltzmann constant, and T is the temperature. According to the proportional formula of hole carrier and impurity concentration, at room temperature, only about 10-8 The proportion of Mg impurities can be activated, and the solubility of Mg in AlN is limited, and the maximum concentration is about 10 20 cm -3 , so the maximum hole concentration of Mg-doped AlN is about 10 12 cm -3 , which is far lower than the actual application requirements of optoelectronic devices (>10 18 cm -3 ).

[0033] At present, in order to achieve high-concentration holes in high-Al component AlGaN, the concentration of Mg doped atoms is usually increased. However, excessive Mg doping may generate Mg single substance, Mg 2 N 3 , Mg-H complexes, etc., which deteriorate the crystal quality and intensify the defect compensation effect, which will further reduce the hole carrier concentration.

[0034] The applicant has found that ion implantation is a non-equilibrium method that uses a high-energy ion beam to impact and penetrate the sample to efficiently incorporate dopants into the sample. This method can introduce a precisely controlled amount of impurities into the sample and is independent of the solubility of the impurities. At the same time, high-temperature annealing can be used to repair implantation-induced damage and effectively activate p-type dopants, which is expected to solve the problem of low doping concentration in high-Al component AlGaN. However, for Mg or Be implantation, due to the high activation energy of p-type dopants, implantation-induced damage can easily compensate for holes in the deep host energy level of the p-type dopant, and it is difficult to obtain a high concentration of holes even with high-dose ion implantation.

[0035] The applicant has found through theoretical calculations that the co-doping technology of p-type dopants (i.e., the first impurity atoms in the present application) and target atoms (i.e., the second impurity atoms in the present application) can simultaneously reduce the formation energy and activation energy of the p-type dopants, improve the stability of the doping system, increase the activation rate of the impurity atoms, and is conducive to the preparation of AlGaN materials with high hole concentrations.

[0036] In view of this, an embodiment of the present application provides a high hole concentration high aluminum component nitride ion implantation co-doping method, comprising: preparing a semiconductor device, the semiconductor device comprising a high aluminum component nitride layer; Ion implantation is performed on the high aluminum component nitride layer to form a p-type doped high aluminum component nitride layer; Among them, ion implantation implants the first impurity atoms and the second impurity atoms into the high-aluminum component nitride layer; the first impurity atoms are used to form p-type doping in the high-aluminum component nitride layer; the second impurity atoms are at least used to reduce the formation energy and activation energy of the first impurity atoms in the high-aluminum component nitride layer.

[0037] The present application can use the first impurity atom as a p-type dopant to achieve p-type doping of the high-aluminum component nitride layer, and can also use the second impurity atom to make the first impurity atom have a lower formation energy and activation energy, thereby improving the stability and activation rate of the first impurity atom in the high-aluminum component nitride layer, thereby increasing the hole concentration after doping, and preparing a p-type doped high-aluminum component nitride with a high hole concentration.

[0038] It should be noted that the high hole concentration high aluminum component nitride ion implantation co-doping method provided in the embodiments of the present application can be used in ultraviolet optoelectronic devices (such as UV-LEDs) of group III-V compound semiconductors, can also be used in electronic devices (such as field effect transistors), and can also be used in the energy field (such as solar cells). The embodiments of the present application do not limit the specific application fields of the high hole concentration high aluminum component nitride ion implantation co-doping method.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] refer to Figure 1 , Figure 1 A schematic flow chart of a high hole concentration high aluminum component nitride ion implantation co-doping method provided in an embodiment of the present application, the high hole concentration high aluminum component nitride ion implantation co-doping method comprising: Step S11: preparing a semiconductor device, wherein the semiconductor device comprises a high aluminum component nitride layer.

[0041] Step S12: performing ion implantation on the high aluminum component nitride layer to form a p-type doped high aluminum component nitride layer.

[0042] Among them, ion implantation implants the first impurity atoms and the second impurity atoms into the high-aluminum component nitride layer; the first impurity atoms are used to form p-type doping in the high-aluminum component nitride layer; the second impurity atoms are at least used to reduce the formation energy and activation energy of the first impurity atoms in the high-aluminum component nitride layer.

[0043] The present application can use the first impurity atom as a p-type dopant to achieve p-type doping of the high-aluminum component nitride layer; the second impurity atom can also be used to make the first impurity atom have a lower formation energy, which can reduce the difficulty of doping the first impurity atom in the high-aluminum component nitride layer; the second impurity atom can also be used to make the first impurity atom have a lower activation energy, thereby reducing the difficulty of ionization of the first impurity atom in the high-aluminum component nitride layer, thereby increasing the hole concentration after doping.

[0044] Moreover, by implementing p-type doping in the high-aluminum component nitride layer through ion implantation, the implantation depth and implantation concentration of the doped atoms can be controlled by changing the ion implantation energy and the ion implantation dose, so that the doped atoms are not limited by solubility; after the ion implantation is completed, the implantation-induced damage is repaired through a high-temperature annealing process to effectively activate the p-type dopant.

[0045] In the embodiment of the present application, when ion implantation is performed, the ion implantation temperature is 500°C to 1000°C, including the end value. During the ion implantation process, high-energy ions will bombard the crystals of the high-aluminum component nitride layer, causing the lattice atoms to shift, forming defects such as vacant sites and interstitial atoms, resulting in damage or destruction of the periodic arrangement of the lattice structure. Within this temperature range, not only can a certain amount of thermal kinetic energy be provided to the lattice atoms, making it easier for them to return to the normal lattice position, but also the lattice damage caused by ion implantation can be reduced.

[0046] In addition, the first impurity atom needs to replace the position of the Al atom to form an effective acceptor impurity. This temperature range can also increase the diffusion ability of the first impurity atom, making it easier to move to a suitable lattice position, while providing energy for the interaction between the first impurity atom and the surrounding atoms, promoting the activation of p-type doping atoms.

[0047] During the ion implantation process, if the temperature is too high, the surface of the high-aluminum component nitride layer may be thermally decomposed and melted, thereby affecting the surface flatness and roughness. In the embodiment of the present application, ion implantation is performed at 500°C to 1000°C to avoid the temperature being too high and affecting the surface morphology, which is crucial for the subsequent steps of lithography and epitaxial growth in the device preparation process, and can improve the yield and performance of the device.

[0048] Optionally, after the ion implantation is completed, the hole concentration in the high aluminum component nitride layer is not less than 10 18 cm -3 Since the second impurity atom can reduce the formation energy and activation energy of the first impurity atom in the high-aluminum component nitride layer, the first impurity atom can have lower formation energy and activation energy. Since the first impurity atom has lower formation energy, the doping difficulty of the first impurity atom in the high-aluminum component nitride layer can be reduced. Since the first impurity atom has lower activation energy, the ionization difficulty of the first impurity atom in the high-aluminum component nitride layer can be reduced, and the hole concentration after doping can be increased, and the hole concentration can be not less than 10 18 cm -3 .

[0049] The embodiment of the present application can make the high aluminum component nitride layer have a thickness of not less than 10 18 cm -3The hole concentration can achieve p-type doping with a large hole concentration in the nitride layer of the high aluminum component, and a higher hole concentration can be achieved compared to the existing doping process. A larger hole concentration can reduce resistance and enhance current transmission capacity, thereby improving the conductivity of the device, improving injection efficiency, and optimizing the pn junction characteristics in the device. For optoelectronic devices, a larger hole concentration can also improve luminous efficiency, optimize threshold voltage, and thus improve the performance of optoelectronic devices.

[0050] Optionally, in the embodiment of the present application, the content of Al in the high aluminum component nitride layer is in the range of 0.7 to 1.0, including the end value. In the conventional p-type doping process, when the content of Al in the high aluminum component nitride layer is in the range of 0.7, the hole concentration after p-type doping is about 10 14 cm -3 , and with the increase of Al content, the hole concentration after p-type doping will gradually decrease. As described above, taking Mg atom as the first impurity atom as an example, when x=1, the highest hole concentration after p-type doping in AlN is about 10 12 cm -3 In the embodiment of the present application, when the content of Al element is in the range of 0.7-1.0, the hole concentration after p-type doping can be increased to 10 18 cm -3 And above, the hole concentration of the high aluminum component nitride layer after p-type doping can be greatly improved.

[0051] In the embodiment of the present application, the high aluminum component nitride layer includes: Al x Ga 1-x N or Al x In 1-x N; where x is the content of Al element. The value range of x is 0.7~1.0, including the endpoint value. Al x Ga 1-x N and Al x In 1-x N can achieve continuous adjustable emission wavelength from 210nm to 1800nm, and is an ideal material for preparing light-emitting devices, which can be used in lighting, display, solid-state lasers and other fields. Based on the embodiments of the present application, Al x Ga 1-x N and Al x In 1-x The hole concentration in N can greatly improve the Al-based x Ga 1-x N and Al x In 1-x NThe performance of semiconductor devices that form pn junctions.

[0052] In the high-aluminum component nitride ion implantation co-doping method with high hole concentration, the first impurity atom is used as a p-type dopant to achieve p-type doping in the high-aluminum component nitride layer. Optionally, the first impurity atom includes at least one of Mg atoms and / or Be atoms. In conventional technology, when the high-aluminum component nitride layer is p-type doped, whether Mg atoms or Be atoms are used to achieve p-type doping, it is limited by the higher formation energy and activation energy of Mg atoms and Be atoms, resulting in a lower hole concentration, and p-type doping with a higher hole concentration cannot be achieved. Moreover, the higher the Al element component, the greater the formation energy and activation energy of Mg atoms and Be atoms, which will further increase the difficulty of p-type doping. In the embodiment of the present application, the co-doping technology of the first impurity atom and the second impurity atom can be used. The formation energy and activation energy of the first impurity atom are reduced by the second impurity atom, and the hole concentration after p-type doping in the high-aluminum component nitride layer can be increased.

[0053] Optionally, the second impurity atom and the Al atom have the same valence electrons, that is, the second impurity atom and the Al atom belong to the same Group III, and the valence electrons of the outermost layers of the two are the same. Therefore, when the second impurity atom replaces the Al atom in the high-aluminum component nitride layer, it will not affect the concentration of carriers (holes and electrons) after doping, so that p-type doping only needs to accurately control the ion implantation dose of the first impurity atom to accurately control the hole concentration.

[0054] In one implementation of the embodiment of the present application, the second impurity atom includes a B atom. As described below, when the B atom and the first impurity atom (Mg atom and / or Be atom) are co-doped in the high-aluminum component nitride layer, the stability and activation rate of the p-type impurities (Mg atom and / or Be atom) in the high-aluminum component nitride layer can be effectively improved, and the hole concentration after p-type doping can be greatly improved.

[0055] Taking the case where the first impurity atom is a Mg atom or a Be atom and the second impurity atom is a B atom as an example, the embodiment of the present application can reduce the activation energy of the first impurity atom that provides holes (as an acceptor atom that provides holes) by about 90 meV, which is 100 times the activation rate when the first impurity atom is doped alone, and the mobility and conductivity of the holes are also significantly improved. Therefore, the embodiment of the present application adopts the method of ion implantation co-doping of the first impurity atom and the B atom, which can not only increase the doping concentration of the p-type doping atom (the first impurity atom), but also improve the activation efficiency of the p-type doping atom, thereby increasing the hole concentration of the high aluminum component nitride layer after p-type doping, and when used in the preparation of optoelectronic devices, it can improve the performance of electrical devices.

[0056] In the embodiment of the present application, the first impurity atom acts as an acceptor atom that provides holes, and it is co-doped with the B atom to achieve p-type doping in the high-aluminum component nitride layer, which can not only reduce the formation energy and activation energy of the acceptor atom, making the doping system more stable, but also significantly improve the activation rate of the acceptor atom, improve the mobility and conductivity of the hole carrier, and thus improve the performance of the optoelectronic device. Therefore, the present application can improve the problem of low solid solubility and high activation energy of the p-type dopant in the high-aluminum component nitride layer, and can achieve p-type doping of the high-aluminum component nitride layer with a high hole concentration by achieving high-concentration doping and reducing the formation energy and activation energy of the p-type dopant.

[0057] refer to Figure 2 , Figure 2 A schematic flow chart of another high hole concentration high aluminum component nitride ion implantation co-doping method provided in an embodiment of the present application, based on the above implementation mode, Figure 2 The high hole concentration high aluminum component nitride ion implantation co-doping method also includes: Step S13: After the ion implantation is completed, a high temperature annealing process is performed to repair implantation-induced damage and activate p-type doping.

[0058] After the first impurity atom performs p-type doping on the high-aluminum component nitride layer, the injection-induced damage easily compensates for the holes in the deep acceptor energy level of the p-type impurity, resulting in that it is difficult to obtain high-concentration holes even with high-dose ion implantation. In the embodiment of the present application, impurity atoms (first impurity atoms and second impurity atoms) can be injected into the high-aluminum component nitride layer by ion implantation, which can destroy the lattice arrangement of the high-aluminum component nitride and generate a large number of group III vacant sites. After high-temperature annealing, the first impurity atom can migrate to the group III vacant site to replace the original group III atom (Al atom), thereby achieving p-type doping. On the other hand, after high-temperature annealing, the injected impurity atom can be migrated to the group III vacant site, and the second impurity atom can be a B atom. The incorporation of the B atom improves the stability of the doping system.

[0059] Optionally, in Figure 1 In the manner shown, the method for performing high temperature annealing treatment includes: placing the semiconductor device in a state filled with N 2 In an environment above 1000°C. This method can perform high-temperature annealing on the high-aluminum component nitride layer after doping in a N-rich atmosphere, so that the first impurity atoms and the second impurity atoms can be co-injected into the high-aluminum component nitride layer to stably replace Al atoms, and the formation energy of the first impurity atoms and the second impurity atoms can be reduced to below 0, indicating that the first impurity atoms and the second impurity atoms can stably exist in the high-aluminum component nitride layer, thereby improving the stability of the doping system. The high-temperature annealing time is set to tens of minutes to several hours depending on the ion implantation energy and dosage.

[0060] Optionally, in one implementation of the embodiment of the present application, when ion implantation is performed, the ion energy of the first impurity atom is 5KeV~100KeV, including the endpoint value; the ion energy of the second impurity atom is 5KeV~100KeV, including the endpoint value. When the ion energy of the impurity atom is 5KeV~100KeV, effective depth ion implantation can be achieved in the high aluminum component nitride layer with a thickness not exceeding 200nm, and high-quality p-type doping can be achieved.

[0061] It should be noted that the numerical ranges provided in the embodiments of the present application include endpoint values; the N-rich environment means annealing in an N-rich environment, and the ion implantation process refers to the injection of impurity atoms into the high-aluminum component nitride layer under vacuum conditions. The embodiments of the present application do not limit the vacuum degree during the ion implantation process, and the required vacuum degree can be set according to product requirements.

[0062] As described below, when the high-hole-concentration high-aluminum component nitride ion implantation co-doping method provided in the embodiment of the present application is used to prepare UVC-LED (extreme ultraviolet light-emitting diode) with a wavelength range of 220nm~250nm, it is necessary to perform p-type doping on the stacked hole injection layer and contact layer. Both the hole injection layer and the contact layer are Al x Ga 1-x The thickness of the N film layer and the hole injection layer can be 50nm~100nm, and the thickness of the contact layer can be 20nm~100nm, and the sum of the thicknesses of the two does not exceed 200nm. Therefore, the ion energy of the impurity atoms provided in this application can achieve effective p-type doping of the hole injection layer and the contact layer.

[0063] When the impurity atom is determined, the mass-to-charge ratio of the impurity atom is a determined constant. If the B atom, the Be atom, and the Mg atom have known mass-to-charge ratios, respectively. Set the mass-to-charge ratio of the first impurity atom to A1, the mass-to-charge ratio of the second impurity atom to A2, the ion injection energy of the first impurity atom to E1, and the ion injection energy of the second impurity atom to E2. In the embodiment of the present application, when ion injection is performed, the ion injection energies of the first impurity atom and the second impurity atom satisfy the formula: (1) In the formula, C is a constant, which is related to the mass-to-charge ratio of the impurity atom used, and can be calibrated by actual doping data or simulation data, which is not limited in the embodiments of the present application. For an impurity atom of a certain element, its atomic mass-to-charge ratio is a certain constant, and the ion implantation energy required to dope it into the high-aluminum component nitride layer is a determinable constant, and the required ion implantation energy is positively correlated with its mass-to-charge ratio. That is to say, the greater the mass-to-charge ratio of an impurity atom of a certain element, the greater the ion implantation energy required to dope it into the high-aluminum component nitride layer. Therefore, when the ion implantation energies of the first impurity atom and the second impurity atom are set to satisfy the above formula (1), the first impurity atom and the second impurity atom can have the same implantation depth in the high-aluminum component nitride layer, and when the first impurity atom and the second impurity atom are co-doped, the formation energy and activation energy of the first impurity atom can be better reduced by the second impurity atom.

[0064] Optionally, during ion implantation, the ion implantation dose of the first impurity atom is 10 13 cm -3 ~10 16 cm -3 The ion implantation dose of the second impurity atom is 10 13 cm -3 ~10 16 cm -3 When the ion implantation dose of impurity atoms is 10 13 cm -3 ~10 16 cm -3 When the hole concentration is large, a high aluminum component nitride layer can be achieved, which can improve the electrical performance of semiconductor devices.

[0065] In one implementation of the embodiment of the present application, when performing ion implantation, the ion implantation dose of the first impurity atom is set to be the same or approximately the same as the ion implantation dose of the second impurity atom. When the first impurity atom and the second impurity atom have the same or approximately the same ion implantation dose, the formation energy and activation energy of the first impurity atom can be better reduced by the second impurity atom, and when the ion implantation doses of the two have a large difference, this effect will be weakened.

[0066] Optionally, when performing ion implantation, the ion implantation angle is 7°. When the first impurity atom and the second impurity atom are implanted into the high-aluminum component nitride layer at an ion implantation angle of 7°, the channel effect can be well suppressed, and the impurity atoms can be accurately controlled to be implanted to a desired depth. By suppressing the channel effect, the depth of the implanted atoms can be prevented from being too large, resulting in a low concentration of acceptor atoms in the high-aluminum component nitride layer, so that the impurity atoms can be more evenly distributed at the desired implantation depth, which is beneficial to improving the stability of electrical and optical properties.

[0067] In addition, the 7° ion implantation angle can also help control the lateral and longitudinal distribution of impurity atoms, achieve more precise impurity doping, improve device performance and reliability, and reduce the damage to other epitaxial layers caused by the ion implantation process. It can maintain the crystal quality of the high-aluminum nitride layer, help maintain its good physical properties, such as high electron mobility, excellent thermal conductivity, etc., and help improve the efficiency and life of electronic and optoelectronic devices.

[0068] In an embodiment of the present application, when performing ion implantation, the first impurity atom may be implanted into the high-aluminum component nitride layer, and then the second impurity atom may be implanted into the high-aluminum component nitride layer; or, when performing ion implantation, the second impurity atom may be implanted into the high-aluminum component nitride layer, and then the first impurity atom may be implanted into the high-aluminum component nitride layer.

[0069] When the first impurity atom and the second impurity atom are co-doped, one can be ion-implanted first and the other can be ion-implanted later. These methods can reduce the formation energy and activation energy of the first impurity atom through the second impurity atom.

[0070] The semiconductor device may be an ultraviolet photoelectric device, such as a UV-LED; the semiconductor device further includes an n-type semiconductor layer; in the semiconductor device, a p-type doped high aluminum component nitride layer is used as a p-type semiconductor layer, and the p-type semiconductor layer and the n-type semiconductor layer form a pn junction of the ultraviolet photoelectric device. Based on the embodiments of the present application, the hole concentration in the p-type semiconductor layer in the ultraviolet photoelectric device can be effectively increased, and its photoelectric performance can be improved.

[0071] In conventional technology, p-type doping in a high-aluminum component nitride layer is mainly achieved by introducing a Mg doping source or a Be doping source during the MOCVD growth process. However, due to the low solid solubility and high activation energy of Mg atoms and Be atoms, it is difficult to achieve p-type doping with a high hole concentration in a high-aluminum component nitride layer. The embodiment of the present application adopts a method of co-doping with a first impurity atom and a second impurity atom, which can effectively improve the doping efficiency of p-type doping in a high-aluminum component nitride layer and greatly increase the hole concentration.

[0072] The high aluminum component nitride ion implantation co-doping method proposed in the embodiment of the present application is used for UV-LED with pn junction. The UV-LED can be a GaN-based UV-LED with a light emission band of 220nm~280nm. Its structure can be as follows: Figure 3 As shown, Figure 3 The figure is a cross-sectional view of a GaN-based UV-LED. The preparation method of the GaN-based UV-LED includes: First, the substrate 101 is placed in a PVD (physical vapor deposition) device to sputter-deposit a buffer layer 102. The buffer layer 102 may be an AlN film layer.

[0073] Then, the substrate 101 with the buffer layer 102 is placed in a MOCVD device and heated to 100°C. 2 Heat treatment at high temperature for 10min~15min in atmosphere. 2 The high-temperature heat treatment in the atmosphere can remove organic pollutants on the surface of the substrate 101 and can also allow the buffer layer 102 made of AlN to recrystallize, thereby improving the quality of nucleation crystals and facilitating subsequent epitaxial growth.

[0074] Furthermore, a superlattice layer 103 is formed on the surface of the buffer layer 102. The superlattice layer 103 may include multiple layers of alternately stacked AlN film layers and AlGaN film layers.

[0075] Furthermore, an n-type semiconductor layer 104 is grown on the surface of the superlattice layer 103 , and the n-type semiconductor layer 104 may be an n-type doped AlGaN film layer.

[0076] Furthermore, a multi-quantum well layer 105 (MQW) is grown on the surface of the n-type semiconductor layer 104 .

[0077] Furthermore, an electron blocking layer 106 is grown on the surface of the multi-quantum well layer 105 , and the electron blocking layer 106 may be an AlGaN film layer.

[0078] Furthermore, an undoped hole injection layer 107 is grown on the surface of the electron blocking layer 106 , and the hole injection layer 107 may be an AlGaN film layer.

[0079] Furthermore, an undoped contact layer 108 is grown on the surface of the hole injection layer 107 , and the contact layer 108 may be an AlGaN film layer.

[0080] The hole injection layer 107 and the contact layer 108 can both be high aluminum component nitride layers. After the contact layer 108 is formed, the hole injection layer 107 and the contact layer 108 can be p-type doped based on the high aluminum component nitride ion implantation co-doping method provided in the embodiment of the present application.

[0081] After the hole injection layer 107 and the contact layer 108 are p-type doped, the device can be placed in N 2 High temperature annealing is performed in an atmosphere to achieve effective activation of p-type impurity atoms.

[0082] Different preparation parameters (such as Al composition and growth temperature) of the multi-quantum well layer 105 in UV-LED will lead to different emission bands. The following is a detailed description of the preparation method of UVC-LED with an emission band of 220nm~250nm in combination with the specific process parameters of each step. The preparation method of UVC-LED includes: Step S21: providing a substrate 101 , which may be any one of a sapphire substrate, a silicon substrate and a silicon carbide substrate.

[0083] Step S22: placing the substrate 101 in a PVD device to form a buffer layer 102 made of AlN on the surface of the substrate 101. As described above, before forming the buffer layer 102, the substrate 101 may be subjected to H 2 High temperature treatment under atmosphere.

[0084] Step S23 : growing an undoped superlattice layer 103 , an n-type semiconductor layer 104 , a multi-quantum well layer 105 , an electron blocking layer 106 , an undoped hole injection layer 107 , and an undoped contact layer 108 in sequence on the surface of the buffer layer 102 .

[0085] In step 23, the specific implementation of each layer may include: First, undoped AlN / Al2O3 is grown on the surface of the buffer layer 102 at a temperature of 1000°C to 1200°C and a pressure of 50 torr to 200 torr. x Ga 1-x N is used as the superlattice layer 103. In the superlattice layer 103, the value of x is 0.6-0.9, the number of superlattice periods is 10-40, the thickness of the AlN film layer is 5nm-15nm, and the Al x Ga 1-x The thickness of the N film layer is 20nm~40nm.

[0086] Then, the temperature is adjusted to 1050°C to 1200°C, and a 1 μm to 4 μm thick n-type doped Al layer is grown on the surface of the superlattice layer 103 under a pressure of 100 torr to 300 torr. x Ga 1-x N is used as the n-type semiconductor layer 104. N-type doped Al x Ga 1-x In N, the value of x is 0.6~0.9, and the concentration of doped Si atoms is 1×10 18 cm -3 ~1×10 19 cm -3 .

[0087] Furthermore, in the n-type doped Al x Ga1-x A multi-quantum well layer 105 is grown on the N surface. The multi-quantum well layer 105 includes 3 to 10 periods of Al x Ga 1-x N / A y Ga 1-y N stacked structure. In the multi-quantum well layer 105, the value of x is 0.7~0.9, the value of y is 0.8~1.0, and x<y. In each period of the multi-quantum well layer 105, Al x Ga 1-x The thickness of N is 2nm~6nm, the growth temperature is 950℃~1100℃, and the pressure is 100torr~500torr; Al y Ga 1-y The thickness of N is 8nm~15nm, the growth temperature is 1000℃~1150℃, and the pressure is 100torr~500torr.

[0088] Further, the temperature is adjusted to 1100° C. to 1200° C. and the pressure is adjusted to 100 torr to 500 torr to grow Al on the surface of the multi-quantum well layer 105. x Ga 1-x N serves as the electron blocking layer 106, wherein the value of x is 0.9-1.0 and the thickness is 30 nm-150 nm.

[0089] Furthermore, under a pressure of 200 torr to 600 torr and a temperature of 950° C. to 1150° C., an undoped Al layer with a thickness of 50 nm to 100 nm is grown on the surface of the electron blocking layer 106. x Ga 1-x N serves as the hole injection layer 107, wherein the value of x is 0.7-1.0.

[0090] Further, the temperature is adjusted to 900°C to 1100°C, and an undoped Al layer with a thickness of 20nm to 100nm is grown on the surface of the hole injection layer 107 under a pressure of 100torr to 600torr. x Ga 1-x N serves as the contact layer 108, wherein the value of x is 0.7~0.8.

[0091] After the epitaxial growth of each film layer is completed, based on the high aluminum component nitride ion implantation co-doping method provided in the embodiment of the present application, p-type doping in the hole injection layer 107 is achieved by co-doping with Mg atoms and B atoms. + and B + The ion implantation energies are 50keV~150keV and 20keV~100keV respectively, and the implantation dose is 1×1013 cm -3 ~1×10 16 cm -3 , the ion incident angle is 7°, and the ion implantation temperature is 500℃~1000℃.

[0092] After the p-type doping of the hole injection layer 107 is completed, Mg atoms and B atoms are implanted into the contact layer 108 to perform p-type doping on the contact layer 108. During the ion implantation process, the Mg + and B + The ion implantation energies are 20keV~100keV and 10keV~80keV respectively, and the implantation dose is 1×10 13 cm -3 ~1×10 16 cm -3 , the ion incident angle is 7°, and the ion implantation temperature is 500℃~1000℃.

[0093] As described above, the lattice damage caused by the ion implantation process can be repaired by high temperature annealing, which can also activate the p-type impurity atoms. 2 In the environment, annealing is continued for 20min~100min.

[0094] refer to Figure 4-Figure 6 , Figure 4-Figure 6 For Figure 3 The schematic diagram of the principle of p-type doping of the high aluminum component nitride layer in the GaN-based UV-LED is shown. The undoped hole injection layer 107 and the undoped contact layer 108 are both Al x Ga 1-x The values ​​of N and x are both greater than 0.7, that is, the Al component is greater than 0.7, and both are high aluminum component nitride layers.

[0095] Before ion implantation, the lattice atoms of the hole injection layer 107 and the contact layer 108 are arranged as follows: Figure 4 After ion implantation, the lattice atoms of the hole injection layer 107 and the contact layer 108 are arranged as shown in FIG. Figure 5 After high temperature annealing, the lattice atoms of the hole injection layer 107 and the contact layer 108 are arranged as shown in FIG. Figure 6 shown.

[0096] In the above-mentioned UVC-LED preparation process, when p-type doping is achieved in the hole injection layer 107 and the contact layer 108 by ion implantation, Mg atoms and B atoms are co-doped as an example. In other methods, Be atoms and B atoms can also be co-doped. At this time, when the hole injection layer 107 is p-doped, the Be atoms formed during the ion implantation process are +and B + The ion implantation energy can be 20keV~100keV, and the implantation dose is 1×10 13 cm -3 ~1×10 16 cm -3 When the contact layer 108 is p-doped, the Be formed during the ion implantation process + and B + The ion implantation energy can be 10keV~80keV, and the implantation dose is 1×10 13 cm -3 ~1×10 16 cm -3 ; Other process parameters can be the same as when co-doping with Mg atoms and B atoms.

[0097] In combination with relevant theoretical models and calculation data, the following describes the effect of the high aluminum component nitride ion implantation co-doping method provided in the application embodiment on reducing the formation energy and activation energy of p-type impurity atoms in the high aluminum component nitride layer and increasing the hole concentration.

[0098] The simulation calculations in this application are performed using the Vienna Ab Initio Simulation Package (VASP) for first-principles simulation calculations based on density functional theory. 0.75 Ga 0.25 N is the research object. Based on the AlN primitive cell, three units are expanded along the a, b, and c directions to obtain a 3×3×3 supercell model, which contains 54 Al atoms and 54 N atoms. a, b, and c are the positive directions of the three axes that are perpendicular to each other in the AlN primitive cell.

[0099] Among them, the high aluminum component nitride ion implantation co-doping method adopts the atomic substitution method, that is, replacing one Al atom with Mg or Be to obtain a doping concentration of 4.36×10 21 cm -3 The doping model, such as Figure 7 As shown, Figure 7 Schematic diagram of the 3×3×3 supercell structure of AlN after p-doping.

[0100] Similarly, replacing three and five Al atoms with Mg or Be gives a doping concentration of 1.31×10 22 cm -3 and 2.18×10 22 cm -3 In the doping model, the substitution of B atoms for Al atoms does not affect the doping concentration. 0.75 Ga 0.25The N supercell model is based on the AlN primitive cell and expands two units along the a, b, and c directions to obtain a 2×2×2 structure, which contains 12 Al atoms, 4 Ga atoms, and 16 N atoms. The high aluminum component nitride ion implantation co-doping method adopts the atomic substitution method to replace one Al atom with Mg or Be to obtain a doping concentration of 2.92×10 21 cm -3 The doping model, such as Figure 8 As shown, Figure 8 After p-doping, Al 0.75 Ga 0.25 Schematic diagram of the 2×2×2 supercell structure of N.

[0101] Among them, after p-type doping, the valence electron configurations of the impurity atoms are Mg: 2p 6 3s 2 、Be:2s 2 , B: 2s 2 2p 1 .

[0102] In order to characterize the difficulty of doping impurities into AlN and the solubility of impurity atoms, the present application calculates the formation energy of impurity atoms based on the constructed model. The formation energy calculation formula is: E f (X q )=E tot (X q )-E tot (bulk)-Σ i n i µ i +q(E VBM +E f )+E corr (2) In formula (2), q represents the charge carried by the impurity atom, E f (X q ) represents the formation energy of charged defects, E tot (X q ) represents the total energy of the doping system, E tot (bulk) represents the total energy of the system without doping. i is the number of atoms corresponding to the defect, µ i It represents the chemical potential of the corresponding defective atom. The chemical potential coefficient of the doped atom entering the system is positive, and the chemical potential coefficient of the atom being replaced and leaving the system is negative. VBM is the valence band maximum, E f is the Fermi level position, E corr Represents the correction term. The greater the formation energy of the acceptor atom, the greater the difficulty of doping and the lower the solubility of the impurity atom.

[0103] Based on the VASP simulation data and the impurity formation energy calculation formula (2), the correlation data between the impurity formation energy in AlN and the Al chemical potential can be obtained as follows: Fig. 9 shown.

[0104] refer to Fig. 9 , Fig. 9 This is a graph showing the relationship between the impurity formation energy and the Al chemical potential in p-type doped AlN. Fig. 9 The horizontal axis is the Al chemical potential μ Al , in eV; the vertical axis is the impurity formation energy (Formation Energy), in eV. In AlN materials, Fig. 9 The changes of formation energy with Al chemical potential when Mg atom is doped alone, Be atom is doped alone, Mg atom and B atom are co-doped, and Be atom and B atom are co-doped are shown respectively. The corresponding relationship curves are Fig. 9 The curve Mg Al 、Curve Be Al , Curve Mg Al +B Al 、Curve Be Al +B Al In N-rich environment, when Be atoms are doped alone and Mg atoms are doped alone, the curve Be Al and curve Mg Al The formation energy is about 0.4eV. A formation energy greater than 0 means that it cannot exist stably in thermodynamics, and the doped atoms tend to precipitate. When Mg atoms and B atoms are co-doped, or Be atoms and B atoms are co-doped, the curve Be Al +B Al and curve Mg Al +B Al The formation energy of Be is reduced to -0.28eV and 0.001eV respectively. The reduction of formation energy below 0 indicates that the process of doping atoms being incorporated into the lattice can proceed spontaneously, and the stability of doping atoms in AlN is increased, which is conducive to obtaining higher doping concentration and hole concentration. Al +B Al The formation energy is the lowest, and theoretically, a higher concentration of Be atoms can be doped into AlN. Fig. 9 The right end of the middle horizontal axis represents an Al-rich environment (Al-rich).

[0105] based on Fig. 9 As shown, the formation energy of p-type impurities Mg atoms and Be atoms can be reduced through the embodiments of the present application, and more stable and higher concentration p-type doping can be achieved in AlN, thereby achieving a higher hole concentration.

[0106] In order to characterize the difficulty of activating doped atoms, this application calculates the activation energy E of acceptor impurity doping based on the constructed model. A , the formula is: E A =E tot [X 0 ]-E tot [X -1 ]-E VBM +E corr (3) In formula (3), E tot [X 0 ] is the total energy of the neutral doping system, E tot [X -1 ] is the total energy of the doping system with a negative charge, E VBM is the valence band maximum, E corr represents the correction term. Among them, the activation energy E A The larger it is, the harder it is for the doped atoms to be ionized and the lower the hole concentration.

[0107] Based on the VASP simulation data and the impurity activation energy calculation formula (3), the relevant data of the impurity activation energy in AlN can be obtained. The change of impurity activation energy can be expressed as Fig.10 shown.

[0108] refer to Fig.10 , Fig.10 is a bar graph of the activation energy of impurities in p-type doped AlN, Fig.10 In the figure, the horizontal axis represents different doping methods, and the vertical axis represents the impurity activation energy (Activation Energy), the unit is meV. Fig.10 The impurity activation energy data for Mg atom doping alone, Be atom doping alone, Mg atom and B atom co-doping, and Be atom and B atom co-doping are shown respectively. The corresponding impurity activation energy bar graphs are Fig.10 The bar graph in Mg Al , Bar chartBe Al , Histogram Mg Al +B Al , Bar chartBe Al +B Al . Histogram Mg Al The activation energy is 465.0 meV, and the bar graph Be Al The activation energy is 396 meV. According to the ratio of hole carriers to impurity concentrations mentioned above, Calculation shows that at room temperature, only about 10 -8 The ratio of Mg atoms to 10 -6When Mg and B atoms are co-doped, the activation energy of Mg atoms is reduced to 386 meV, and the activation ratio of Mg atoms at room temperature is increased to about 10 -6 When Be atoms and B atoms are co-doped, the activation energy of Be atoms is reduced to 302 meV, and the activation ratio of Be atoms at room temperature is increased to 10 -4 Therefore, the co-incorporation of acceptor impurities and B atoms will significantly increase the activation ratio of acceptor impurity atoms, thereby increasing the hole concentration in the AlN material.

[0109] refer to Fig.11 and Fig.12 , Fig.11 The bar graphs are of the formation energy when Mg atoms are doped alone and co-doped with B atoms in AlN materials with different doping concentrations in N-rich environments. Fig.12 This is a bar graph of the formation energy when Be atoms are doped alone and co-doped with B atoms in AlN materials with different doping concentrations in a N-rich environment. Fig.11 and Fig.12 In the figure, the horizontal axis represents the doping concentration (Doping concentration), the unit is cm -3 ; The vertical axis represents the impurity formation energy, the unit is eV.

[0110] Fig.11 The three bar graphs above show the formation energy bar graphs corresponding to three different doping concentrations when Mg atoms are doped alone. Al The three bar graphs below are the formation energy bar graphs of Mg atoms and B atoms at the three doping concentrations. Al +B Al . Fig.12 The three bar graphs above represent the formation energy bar graphs corresponding to three different doping concentrations when Be atoms are doped alone. Al The three bar graphs below are the formation energy bar graphs of Be atoms and B atoms at the three doping concentrations. Al +B Al .

[0111] based on Fig.11 and Fig.12 It can be seen that as the doping concentration increases from 4.36×10 21 cm -3 Increased to 2.28×10 22 cm -3 , histogram Mg Al and histogram Be Al The formation energy of AlN increases, that is, as the doping concentration increases, it becomes increasingly difficult for Mg atoms to be incorporated into the lattice. However, when Mg atoms or Be atoms and B atoms are co-doped into AlN, the bar graph shows that MgAl +B Al and histogram Be Al +B Al The formation energy of AlN is on a downward trend, and the formation energy value is negative, which means that with the increase of doping concentration, the system becomes more and more stable, that is, the doping atoms are more and more easily incorporated into the lattice. It can be seen that the co-doping of Mg atoms or Be atoms and B atoms is conducive to achieving high-concentration p-type doping in AlN materials.

[0112] refer to Fig.13 , Fig.13 P-type doped Al 0.75 Ga 0.25 The relationship between the impurity formation energy in N and the chemical potential of Al, Fig.13 In the figure, the horizontal axis is the Al chemical potential μ Al , the unit is eV; the vertical axis is the impurity formation energy, the unit is eV. Al 0.75 Ga 0.25 In N material, Fig.13 The changes of formation energy with Al chemical potential when Mg atom is doped alone, Be atom is doped alone, Mg atom and B atom are co-doped, and Be atom and B atom are co-doped. The corresponding relationship curves are as follows: Fig.13 The curve Mg Al 、Curve Be Al , Curve Mg Al +B Al 、Curve Be Al +B Al .like Fig.13 As shown in the figure, in a N-rich environment, when Mg atoms and Be atoms are doped separately, the curve Mg Al and curve Be Al The formation energies of Mg and Be are 0.39eV and 0.34eV respectively, which are thermodynamically unstable and the metal atoms tend to precipitate. When Mg or Be atoms are co-doped with B atoms, the curve Mg Al +B Al and curve Be Al +B Al The formation energy of the doping atoms is reduced to 0.01eV and -0.1eV respectively. The reduction of the formation energy makes it easier for the doping atoms to be incorporated into the lattice, which can increase the doping atoms in the Al 0.75 Ga 0.25 The solubility of N in N is conducive to obtaining higher doping concentration and hole concentration. Curve Be Al +B Al The formation energy is the lowest. Theoretically, Al 0.75 Ga 0.25 N materials can be doped with higher concentrations of Be atoms. Fig.13The right end of the middle horizontal axis represents an Al-rich environment (Al-rich).

[0113] refer to Fig.14 , Fig.14 P-type doped Al 0.75 Ga 0.25 Histogram of activation energy of impurities in N, Fig.14 In the figure, the horizontal axis represents different doping methods, and the vertical axis represents the impurity activation energy (Activation Energy), the unit is meV. Fig.14 The impurity activation energy data for Mg atom doping alone, Be atom doping alone, Mg atom and B atom co-doping, and Be atom and B atom co-doping are shown respectively. The corresponding impurity activation energy bar graphs are Fig.14 The bar graph in Mg Al , Bar chartBe Al , Histogram Mg Al +B Al , Bar chartBe Al +B Al .

[0114] Based on VASP simulation data and impurity activation energy calculation formula (3), we can obtain Fig.14 The bar graph shown, bar graph Mg Al The activation energy is 422.3 meV, and the bar graph Be Al The activation energy of the acceptor impurity is 279.3 meV. When Mg atoms and B atoms are co-doped, the activation energy is reduced to 230.5 meV, and when Be atoms and B atoms are co-doped, the activation energy is reduced to 106.8 meV. Therefore, the co-doping of acceptor impurities and B atoms will reduce the activation energy of acceptor impurities, increase the activation ratio of impurity atoms, and thus increase the activation ratio of Al 0.75 Ga 0.25 Hole concentration in N material.

[0115] In order to characterize the transport characteristics of hole carriers ionized by acceptor impurities in the directions parallel to and perpendicular to the c-axis, this application calculates the hole effective mass, hole carrier mobility, and hole carrier conductivity after doping based on the constructed model. The formula for the hole effective mass is: (4) In formula (4), is the effective mass of the hole near the top of the valence band, k represents the wave vector, represents the corresponding energy at k, represents Planck's constant.

[0116] The calculation formula of hole mobility is: (5) In formula (5), is the hole mobility, is the unit charge, is the relaxation time.

[0117] Hole conductivity The calculation formula is: (6) In formula (6), is the hole carrier concentration.

[0118] refer to Figure 15-18 , Fig.15 This is the energy band structure diagram when Mg atoms are doped alone in AlN material. Fig.16 This is the energy band structure diagram when Mg atoms and B atoms are co-doped in AlN material. Fig.17 This is the energy band structure diagram when Be atoms are doped alone in AlN material. Fig.18 This is the energy band structure diagram when Be atoms and B atoms are co-doped in AlN material. Figure 15-18 The middle horizontal axis represents the high symmetry points in the unit cell. Figure 15-18 The figure shows five high symmetry points Γ, M, K, and A on the horizontal axis; the vertical axis represents the energy of different energy bands (Energy), in eV. Figure 15-18 In the four energy band structure diagrams shown, the Fermi level has entered the valence band, indicating that p-type doping has been achieved. Figure 15-18 As shown in the band structure diagram, by taking the second-order derivative of the energy curve along the directions of Γ→K and Γ→A, the effective mass of holes perpendicular to the c-axis and parallel to the c-axis can be obtained respectively.

[0119] According to the band structure and effective mass calculation formula (4), as shown in Tables 1 and 2, the effective hole masses (m) of the crystal field splitting band (ch), heavy hole band (hh) and light hole band (lh) along the c-axis direction (⊥) and perpendicular to the c-axis direction ( / / ) can be obtained. * Based on the effective mass, using formula (5) and formula (6), as shown in Table 3 and Table 4, the mobility and conductivity of hole carriers can be obtained.

[0120] Table 1 Changes in effective carrier mass of different hole bands in doped AlN

[0121] Table 2 Changes in effective carrier mass of different hole bands in doped AlN

[0122] Table 3 Carrier mobility ratios of different hole bands in doped AlN

[0123] Table 4 Carrier conductivity ratios of different hole bands in doped AlN

[0124] In Table 1, Table 2, Table 3 and Table 4, a) is the direction perpendicular to the c-axis; b) is the direction parallel to the c-axis.

[0125] As shown in Table 1, compared with Mg atom doping alone, after Mg and B atoms are co-doped, the effective mass of the ch band shows a downward trend in the direction parallel to the c-axis and slightly increases in the direction perpendicular to the c-axis, and the effective mass of the light and heavy hole bands shows a downward trend in both the directions parallel to the c-axis and perpendicular to the c-axis.

[0126] As shown in Table 2, compared with Be atom doping alone, after Be and B atoms are co-doped, the effective mass of the ch band shows a downward trend in the direction parallel to the c-axis, and is basically unchanged in the direction perpendicular to the c-axis. The effective mass of the light hole band is basically unchanged in the direction parallel to the c-axis, and decreases significantly in the direction perpendicular to the c-axis. The effective mass of the heavy hole band decreases significantly in the direction parallel to the c-axis, and increases slightly in the direction perpendicular to the c-axis.

[0127] Based on the calculation results of effective masses of different hole bands, Table 3 lists the ratio of hole mobility of Mg atom or Be atom and B atom co-doping to Mg atom or Be atom doping alone. Based on the results of Table 3, Table 4 lists the ratio of hole conductivity of Mg atom or Be atom and B atom co-doping to Mg atom or Be atom doping alone. When Mg atom and B atom are co-doped, the hole conductivity of ch band, heavy hole band and light hole band in the direction perpendicular to the c-axis is 2.9, 6.8 and 6.3 times that of Mg doping alone, respectively; in the direction parallel to the c-axis, the hole conductivity of ch band, heavy hole band and light hole band is 4.1, 5.3 and 5.4 times that of Mg doping alone, respectively. When Be atoms and B atoms are co-doped, the hole conductivities of the ch band, heavy hole band and light hole band in the direction perpendicular to the c-axis are 3.6, 16.3 and 10.3 times those when Be is doped alone, respectively; in the direction perpendicular to the c-axis, the hole conductivities of the ch band, heavy hole band and light hole band are 4.2, 10.5 and 13.0 times those when Mg is doped alone, respectively; therefore, the co-doping technology of Mg atoms and B atoms or Be atoms and B atoms is not only beneficial to the lateral transport of holes in AlN materials, but also more beneficial to the injection of holes in the vertical direction.

[0128] Based on the data in Table 3 and Table 4, it can be seen that based on the technical solution of the present application, the high aluminum component nitride layer AlN can have greater conductivity and mobility in the vertical direction after p-type doping. For optoelectronic devices, its film structure is as follows Figure 3As shown, they are stacked in the vertical direction, so the greater conductivity and mobility in the vertical direction can make the device have better transmission performance in the vertical direction, thereby improving the photoelectric performance of the device.

[0129] Based on the above description, in the technical solution of the present application, a solution of co-doping the first impurity atom and the second impurity atom can be adopted to reduce the formation energy and activation energy of the first impurity atom as the acceptor atom.

[0130] On the one hand, the ion implantation process in the technical solution of the present application is carried out in a vacuum system, which can ensure that the doped ions have a high purity. By changing the ion implantation energy and the ion implantation dose, the implantation depth and the implantation concentration of the doped ions can be precisely controlled. It is not limited by the solubility of the doping source and can achieve high-concentration doping of high-aluminum component nitrides.

[0131] On the other hand, for the high-aluminum component nitride layer, the solubility of Mg atoms and Be atoms at room temperature is low, and the activation energy is high. Even if ions are implanted with high-concentration acceptor atoms, it is difficult to achieve effective activation, and it is very difficult to achieve p-type doping with high hole concentration. In the embodiment of the present application, according to the first-principles calculation results, in a N-rich atmosphere, p-type impurity atoms (Mg atoms and / or Be) and B atoms are co-injected into the high-aluminum component nitride layer to replace Al atoms, and the formation energy of p-type impurity atoms can be reduced to below 0, indicating that p-type impurity atoms can exist stably in the high-aluminum component nitride layer, thereby improving the stability of the doping system. In addition, the co-doping method of Mg atoms or Be atoms and B atoms can reduce the activation energy of the acceptor impurity by about 90 meV, which is 100 times the activation rate when the acceptor atom is doped alone, and the mobility and conductivity of the hole carrier can also be significantly improved. Therefore, the technical solution of the present application can not only increase the doping concentration of p-type impurity atoms, but also improve the activation efficiency of p-type impurity atoms, thereby increasing the hole concentration of the high aluminum component nitride layer after p-type doping. When used in optoelectronic devices, it can improve the performance of optoelectronic devices.

[0132] In the specification of this application, each embodiment is described in a progressive, parallel, or progressive and parallel manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. The embodiments provided in the embodiments of this application can be combined with each other if there is no contradiction.

[0133] It should be noted that in the description of the present application, it should be understood that the description of the drawings and embodiments is illustrative rather than restrictive. The same reference numerals throughout the embodiments of the specification identify the same structure. In addition, for the sake of understanding and ease of description, the drawings may exaggerate the thickness of some layers, films, panels, regions, etc. It is also understood that when an element such as a layer, film, region, or substrate is referred to as "on" another element, the element may be directly on the other element or there may be an intermediate element. In addition, "on" refers to positioning an element on or below another element, but does not essentially refer to positioning on the upper side of another element according to the direction of gravity.

[0134] The terms "upper", "lower", "top", "bottom", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0135] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the article or device including the above elements.

[0136] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-hole-concentration high-aluminum component nitride ion implantation co-doping method, characterized in that: include: preparing a semiconductor device, the semiconductor device comprising a high aluminum component nitride layer; Performing ion implantation on the high aluminum component nitride layer to form a p-type doped high aluminum component nitride layer; Among them, the ion implantation implants the first impurity atoms and the second impurity atoms into the high-aluminum component nitride layer; the first impurity atoms are used to form p-type doping in the high-aluminum component nitride layer; the second impurity atoms are at least used to reduce the formation energy and activation energy of the first impurity atoms in the high-aluminum component nitride layer.

2. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: After the ion implantation is completed, the hole concentration in the high aluminum component nitride layer is not less than 10 18 cm -3 .

3. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: In the high aluminum component nitride layer, the content of Al element ranges from 0.7 to 1.0, including the endpoint values.

4. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 3, characterized in that: The high aluminum component nitride layer comprises: Al x Ga 1-x N or Al x In 1-x N; Wherein, x is the content of Al element.

5. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: The first impurity atoms include at least one of Mg atoms and / or Be atoms.

6. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: The second impurity atom has the same valence electrons as the Al atom.

7. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 6, characterized in that: The second impurity atoms include B atoms.

8. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: Also includes: After the ion implantation is completed, a high temperature annealing process is performed to repair implantation-induced damage and activate the p-type doping.

9. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 8, characterized in that: The method for performing the high temperature annealing treatment comprises: The semiconductor device is placed in an environment filled with N2 at a temperature above 1000°C.

10. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: During ion implantation, the ion energy of the first impurity atoms is 5KeV~100KeV, including the endpoint values; the ion energy of the second impurity atoms is 5KeV~100KeV, including the endpoint values.

11. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: The mass-to-charge ratio of the first impurity atom is A1, the mass-to-charge ratio of the second impurity atom is A2, the ion implantation energy of the first impurity atom is E1, and the ion implantation energy of the second impurity atom is E2; During ion implantation, the ion implantation energies of the first impurity atoms and the second impurity atoms satisfy: ； Where C is a constant.

12. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: When performing ion implantation, the ion implantation dose of the first impurity atom is 10 13 cm -3 ~10 16 cm -3 The ion implantation dose of the second impurity atom is 10 13 cm -3 ~10 16 cm -3 .

13. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: When performing ion implantation, the ion implantation dosage of the first impurity atoms is the same as the ion implantation dosage of the second impurity atoms.

14. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: When ion implantation is performed, the ion implantation angle is 7°.

15. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: During ion implantation, the first impurity atoms are implanted into the high-aluminum component nitride layer, and then the second impurity atoms are implanted into the high-aluminum component nitride layer; Alternatively, during ion implantation, the second impurity atoms are implanted into the high-aluminum component nitride layer, and then the first impurity atoms are implanted into the high-aluminum component nitride layer.

16. The high hole concentration high aluminum component nitride ion implantation co-doping method according to claim 1, characterized in that: When performing ion implantation, the ion implantation temperature is 500°C to 1000°C, both inclusive.

17. The high hole concentration high aluminum component nitride ion implantation co-doping method according to any one of claims 1 to 16, characterized in that: The semiconductor device is an ultraviolet photoelectric device; the semiconductor device also includes an n-type semiconductor layer; The p-type doped high aluminum component nitride layer serves as a p-type semiconductor layer, and forms a pn junction of the ultraviolet photoelectric device with the n-type semiconductor layer.

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