A high-performance self-powered diamond-based heterojunction solar-blind detector

Abstract

The present invention discloses a high-performance self-powered diamond-based heterojunction solar-blind detector, which comprises, from bottom to top, a diamond single crystal substrate, a p-type diamond film, a Ga polarity control layer, an intrinsic i-Ga2O3 light absorption layer, a δ modulation doping layer, an AlO dielectric layer and a top interdigitated electrode; the cross-sectional length of the diamond single crystal substrate is consistent with the cross-sectional length of the p-type diamond film; the cross-sectional lengths of the Ga polarity control layer, the intrinsic i-Ga2O3 light absorption layer, the δ modulation doping layer and the AlO dielectric layer are all the same; and the Ga polarity control layer is the same as the Ga polarity control layer. The cross-sectional length of the control layer is smaller than that of the p-type diamond film; the Ga polarity control layer, the intrinsic i-Ga2O3 light absorption layer, the δ modulation doping layer, and the AlO dielectric layer are arranged in the middle of the p-type diamond film; two p-type diamond films are provided on the p-type diamond film; the p-type diamond film is located on both sides of the Ga polarity control layer; the top interdigitated electrode is embedded in the AlO dielectric layer; the δ modulation doping layer adopts periodic δ-type modulation doping technology to perform n-type Ga2O3 doping to obtain a high concentration of carriers.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric detection chips, and more specifically to a high-performance self-powered diamond-based heterojunction solar-blind detector. Background Art

[0002] Ultra-wide bandgap semiconductor solar-blind ultraviolet (UV) detection has gained widespread attention in recent years due to its important applications in military early warning, target identification, guidance, and environmental monitoring. Diamond, a leading ultra-wide bandgap semiconductor, exhibits strong radiation resistance, high thermal conductivity, and a high breakdown electric field. Its absorption in the extreme ultraviolet (EUV) region (<210nm) makes it ideal for deep UV detection in extreme environments.

[0003] However, it has some shortcomings: the light absorption coefficient in the solar-blind band is small and n-type doping is difficult. Therefore, the light response of a single diamond detector in the solar-blind band is weak, making it difficult to directly apply. Compared with diamond, the semiconductor band gap of gallium oxide (Ga2O3) is 5.0eV, and its light absorption coefficient in the solar-blind band is greater than 10 5 cm -1 , making it an ideal material for solar-blind photodetection. However, its drawbacks include low thermal conductivity and difficulty in p-type doping, making Ga2O3 detectors incapable of self-powering. Addressing the challenges of diamond-based solar-blind detectors, such as weak light absorption and a lack of self-powering capability, is gaining increasing attention. Summary of the Invention

[0004] In order to solve the problems of the above-mentioned deficiencies and defects of the existing ultra-wide bandgap semiconductor solar-blind detectors, the present invention provides a high-performance self-powered diamond-based heterojunction solar-blind detector.

[0005] In order to achieve the above-mentioned purpose of the present invention, the technical solutions adopted are as follows:

[0006] A high-performance self-powered diamond-based heterojunction solar-blind detector, comprising, from bottom to top, a diamond single crystal substrate, a p-type diamond thin film, a Ga polarity control layer, an intrinsic i-Ga2O3 light absorption layer, a delta modulation doping layer, an AlO dielectric layer, and a top interdigitated electrode;

[0007] The cross-sectional length of the diamond single crystal substrate is consistent with the cross-sectional length of the p-type diamond film;

[0008] The cross-sectional lengths of the Ga polarity control layer, the intrinsic i-Ga2O3 light absorption layer, the δ modulation doping layer, and the AlO dielectric layer are all the same;

[0009] The cross-sectional length of the Ga polarity control layer is smaller than the cross-sectional length of the p-type diamond film;

[0010] The Ga polarity control layer, the intrinsic i-Ga2O3 light absorption layer, the delta modulation doping layer, and the AlO dielectric layer are arranged in the middle of the p-type diamond film;

[0011] Two diamond electrodes are provided on the p-type diamond film; the diamond electrodes are located on both sides of the Ga polarity control layer;

[0012] The top interdigitated electrode is embedded in the AlO dielectric layer;

[0013] The delta modulation doping layer adopts periodic delta modulation doping technology to perform n-type Ga2O3 doping to obtain high-concentration carriers.

[0014] Preferably, the top interdigitated electrode comprises a first electrode structure having a rectangular cross section and a second electrode structure disposed below the first electrode structure; the cross section of the second electrode structure is a trapezoid;

[0015] Wherein, the first electrode structure is arranged on top of the AlO dielectric layer;

[0016] The second electrode structure is embedded in the AlO dielectric layer; the second electrode structure is embedded in a relatively long first bottom surface connected to the bottom of the first electrode structure; the second electrode structure is embedded in a relatively short second bottom surface connected to the top of the δ modulation doping layer.

[0017] Furthermore, there are at least two top interdigitated electrodes.

[0018] Preferably, the p-type diamond film is grown by MPCVD on a diamond single crystal substrate using borane BH3 as a doping source.

[0019] Preferably, the Ga polarity control layer, the intrinsic i-Ga2O3 light absorption layer, and the delta modulation doping layer are all grown sequentially from bottom to top on the p-type diamond film using radio frequency MBE.

[0020] Preferably, MBE is used for atomic-level regulation to sequentially grow i-Ga2O3 / Sn:Ga2O3 modulation-doped superlattice on the intrinsic i-Ga2O3 layer to obtain a δ modulation-doped layer.

[0021] Preferably, the top interdigitated electrode and the delta modulation doping layer constitute a top interdigitated Ga2O3 electron collector; and the p-type diamond film serves as a diamond hole collector for photogenerated carriers.

[0022] Preferably, the diamond electrode is completed by constructing a heavily doped ohmic contact region in a p-diamond hole collector with a low B concentration using ion implantation.

[0023] Furthermore, the preparation of the detector first uses wet etching and ICP etching to pattern the β-Ga2O3 layer, and sputters the oxide dielectric passivation layer; secondly, photolithography is used to prepare the p-type diamond ohmic contact electrode, and the insulating dielectric isolation layer and passivation are sputtered, the diamond electrode is patterned and the contact electrode is completed; finally, the top interdigitated Ga2O3 electron collector is prepared.

[0024] Furthermore, the top interdigitated electrodes are integrated into a two-dimensional array to form a light detection chip, and a single detector unit is integrated with an active matrix driving unit to construct a complete single pixel.

[0025] The beneficial effects of the present invention are as follows:

[0026] To address the challenges faced by single diamond-based solar-blind UV detectors, such as low light absorption coefficient, low mobility, difficulty in n-type doping, and lack of self-power supply capability, the present invention uses thermodynamically stable β-phase Ga2O3 as a heterojunction matching material to complement its advantages.

[0027] The design of the top interdigitated electrode in this invention allows for flexible adjustment of the light-absorbing layer electrode. A high-field region is constructed between the p-type diamond film, which serves as the diamond hole collector, the intrinsic Ga2O3 light absorption region, and the top interdigitated Ga2O3 electron collector. This allows for efficient separation and collection of electron-hole pairs excited by solar-blind photons. This eliminates parasitic capacitance of the diamond bottom electrode and suppresses carrier depletion caused by the "recombination effect." BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the high-performance self-powered diamond-based heterojunction solar-blind detector described in the present invention.

[0029] In the figure, 1-diamond single crystal substrate, 2-p-type diamond film, 3-diamond electrode, 4-Ga polarity control layer, 5-i-Ga2O3 light absorption layer, 6-δ modulation doping layer, 7-AlO dielectric layer, 8-top interdigitated electrode, 801-first electrode structure, 802-second electrode structure. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] like Figure 1 As shown, a high-performance self-powered diamond-based heterojunction solar-blind detector comprises, from bottom to top, a diamond single crystal substrate 1, a p-type diamond film 2, a Ga polarity control layer 4, an intrinsic i-Ga2O3 light absorption layer 5, a delta modulation doping layer 6, an AlO dielectric layer 7, and a top interdigitated electrode 8;

[0033] The cross-sectional length of the diamond single crystal substrate 1 is consistent with the cross-sectional length of the p-type diamond film 2;

[0034] The Ga polarity control layer 4, the intrinsic i-Ga2O3 light absorption layer 5, the delta modulation doping layer 6, and the AlO dielectric layer 7 all have the same cross-sectional length;

[0035] The cross-sectional length of the Ga polarity control layer 4 is smaller than the cross-sectional length of the p-type diamond film 2;

[0036] The Ga polarity control layer 4, the intrinsic i-Ga2O3 light absorption layer 5, the delta modulation doping layer 6, and the AlO dielectric layer 7 are arranged in the middle position of the p-type diamond film 2;

[0037] Two diamond electrodes 3 are provided on the p-type diamond film 2; the diamond electrodes 3 are located on both sides of the Ga polarity control layer 4;

[0038] The top interdigitated electrode 8 is embedded in the AlO dielectric layer 7;

[0039] The delta modulation doping layer 6 adopts periodic delta modulation doping technology to perform n-type Ga2O3 doping to obtain high-concentration carriers.

[0040] In a specific embodiment, the top interdigitated electrode 8 includes a first electrode structure 801 having a rectangular cross section and a second electrode structure 802 disposed below the first electrode structure 801; the cross section of the second electrode structure 802 is a trapezoid;

[0041] Wherein, the first electrode structure 801 is arranged on top of the AlO dielectric layer 7;

[0042] The second electrode structure 802 is embedded in the AlO dielectric layer 7; and the second electrode structure 802 is embedded with a relatively long first bottom surface connected to the bottom of the first electrode structure 801; the second electrode structure 802 is embedded with a relatively short second bottom surface connected to the top of the δ modulation doping layer 6.

[0043] In a specific embodiment, there are at least two top interdigital electrodes 8. Several top interdigital electrodes 8 form a self-aligned coplanar top interdigital electrode structure.

[0044] To address the challenges faced by single diamond-based solar-blind UV detectors, such as low light absorption coefficient, low mobility, difficulty in n-type doping, and lack of self-power supply capability, the present invention uses thermodynamically stable β-phase Ga2O3 as a heterojunction matching material to complement its advantages.

[0045] The present invention's design of the top interdigitated electrode 8 allows for flexible adjustment of the light-incident surface electrode. A spatial high-field strength region is constructed between the p-type diamond film 2, which serves as the diamond hole collector, the intrinsic Ga2O3 light absorption region, and the top interdigitated Ga2O3 electron collector, enabling efficient separation and collection of electron-hole pairs excited by solar-blind photons. This eliminates parasitic capacitance of the diamond bottom electrode and suppresses carrier depletion caused by the "recombination effect." This embodiment also incorporates a composite oxide high-K insulating layer dielectric material as the wrapping layer for the entire detector, reducing mesa edge leakage current.

[0046] Example 2

[0047] like Figure 1 As shown, a high-performance self-powered diamond-based heterojunction solar-blind detector comprises, from bottom to top, a diamond single crystal substrate 1, a p-type diamond film 2, a Ga polarity control layer 4, an intrinsic i-Ga2O3 light absorption layer 5, a delta modulation doping layer 6, an AlO dielectric layer 7, and a top interdigitated electrode 8;

[0048] The cross-sectional length of the diamond single crystal substrate 1 is consistent with the cross-sectional length of the p-type diamond film 2;

[0049] The Ga polarity control layer 4, the intrinsic i-Ga2O3 light absorption layer 5, the delta modulation doping layer 6, and the AlO dielectric layer 7 all have the same cross-sectional length;

[0050] The cross-sectional length of the Ga polarity control layer 4 is smaller than the cross-sectional length of the p-type diamond film 2;

[0051] The Ga polarity control layer 4, the intrinsic i-Ga2O3 light absorption layer 5, the delta modulation doping layer 6, and the AlO dielectric layer 7 are arranged in the middle position of the p-type diamond film 2;

[0052] Two diamond electrodes 3 are provided on the p-type diamond film 2; the diamond electrodes 3 are located on both sides of the Ga polarity control layer 4;

[0053] The top interdigitated electrode 8 is embedded in the AlO dielectric layer 7;

[0054] The delta modulation doping layer 6 adopts periodic delta modulation doping technology to perform n-type Ga2O3 doping to obtain high-concentration carriers.

[0055] In a specific embodiment, the top interdigitated electrode 8 includes a first electrode structure 801 having a rectangular cross section and a second electrode structure 802 disposed below the first electrode structure 801; the cross section of the second electrode structure 802 is a trapezoid;

[0056] Wherein, the first electrode structure 801 is arranged on top of the AlO dielectric layer 7;

[0057] The second electrode structure 802 is embedded in the AlO dielectric layer 7; and the second electrode structure 802 is embedded with a relatively long first bottom surface connected to the bottom of the first electrode structure 801; the second electrode structure 802 is embedded with a relatively short second bottom surface connected to the top of the δ modulation doping layer 6.

[0058] In a specific embodiment, there are at least two top interdigital electrodes 8. Several top interdigital electrodes 8 form a self-aligned coplanar top interdigital electrode structure.

[0059] In a specific embodiment, the p-type diamond film 2 is grown on a diamond single crystal substrate 1 by MPCVD using borane BH 3 as a doping source.

[0060] Preferably, the Ga polarity control layer 4, the intrinsic i-Ga2O3 light absorption layer 5, and the delta modulation doping layer 6 are all grown sequentially from bottom to top on the p-type diamond film 2 using radio frequency MBE.

[0061] This embodiment combines diamond with Ga2O3 thin film to construct a heterojunction pin (PIN) UV solar-blind detector, leveraging the respective and complementary advantages of the two ultra-wide bandgap semiconductors. An innovative periodic delta-modulated doping technique is employed for n-type Ga2O3 doping, achieving a high carrier concentration. The self-aligned coplanar top interdigitated structure effectively suppresses parasitic capacitance, enabling its application in next-generation diamond-based UV solar-blind detector chip technology.

[0062] In this embodiment, the MPCVD is microwave plasma chemical vapor deposition, the MBE is molecular beam epitaxy, and the ICP etching is inductively coupled plasma etching.

[0063] In a specific embodiment, MBE is used for atomic-level control to sequentially grow an i-Ga2O3 / Sn:Ga2O3 modulation-doped superlattice on the intrinsic i-Ga2O3 light-absorbing layer to form a delta modulation-doped layer 6. This reduces the Sn acceptor ionization energy in the Ga2O3 film and simultaneously suppresses the formation of point defects and dislocation lines.

[0064] In a specific embodiment, the diamond electrode 3 is completed by constructing a heavily doped ohmic contact region in a p-diamond hole collector with a low B concentration through ion implantation.

[0065] In a specific embodiment, the top interdigitated electrode 8 and the delta modulation doping layer 6 constitute a top interdigitated Ga2O3 electron collector; the p-type diamond film 2 serves as a diamond hole collector for photogenerated carriers.

[0066] In a specific embodiment, the detector is prepared by first patterning the β-Ga2O3 layer using wet etching and ICP etching, and sputtering the oxide dielectric passivation layer; secondly, photolithography is used to prepare the p-type diamond ohmic contact electrode, and the insulating dielectric isolation layer and passivation are sputtered, the diamond electrode 3 is patterned and the contact electrode is completed; finally, the top interdigitated Ga2O3 electron collector is prepared.

[0067] In a specific embodiment, the top interdigitated electrodes 8 are integrated into a two-dimensional array to form a light detection chip, and a single detector unit is integrated with an active matrix driving unit to construct a complete single pixel.

[0068] Example 3

[0069] Based on the high-performance self-powered diamond-based heterojunction solar-blind detector described in Example 2, the detector is specifically prepared as follows:

[0070] First, software was used to simulate the characteristics of the Ga and O polar growth surfaces of Ga2O3 materials, studying their influence on the crystal phase, dangling bonds, and interface energy bands. The formation energies of various point defects in β-phase Ga2O3 were analyzed, particularly the formation energy of oxygen vacancies in different compositions and their impact on carrier concentration and film conductivity, thus guiding subsequent growth and fabrication.

[0071] Subsequently, a boron-doped p-type diamond film 2 was grown on a diamond single crystal substrate 1 using MPCVD, using borane (BH3) as the doping source. By systematically studying the effects of different single-crystal diamond growth planes, interface control, and growth processes on boron doping, the team achieved a high-quality p-type diamond film 2 with a high boron acceptor concentration, low defects, and low ionization energy. By optimizing interface control, the formation of interface states was suppressed, deep-level traps were reduced, and the hole concentration in the p-type diamond film 2 was effectively increased.

[0072] MBE was used to sequentially grow a low-temperature metal Ga layer, a low-temperature intrinsic Ga2O3 layer, and a high-temperature Ga2O3 layer on a p-type diamond film 2. The low-temperature intrinsic Ga2O3 and high-temperature Ga2O3 layers served as intrinsic i-Ga2O3 light absorption layers, and the low-temperature metal Ga layer served as a Ga polarity control layer (4). The metal Ga layer can effectively release stress, promote the growth of Ga polarity surfaces, reduce the density of point defects and dislocation lines within the Ga2O3 film, and explore the Ga2O3 film control parameters for the Ga polarity growth surface. By fine-tuning the Ga / O atomic ratio, the optimization of high-quality β-Ga2O3 single crystal films was achieved.

[0073] Using periodic delta-modulation doping, an i-Ga2O3 / Sn:Ga2O3 modulated-doped superlattice is sequentially grown on the intrinsic i-Ga2O3 light-absorbing layer, resulting in delta-modulated doped layer 6. This structure effectively reduces the Sn acceptor ionization energy within the Ga2O3 film while suppressing the formation of point defects and dislocation lines. By varying the growth parameters of the Ga2O3 modulated-doped superlattice at varying thicknesses, high electron concentration and mobility are simultaneously optimized.

[0074] Software was used to construct a p-diamond / i-Ga2O3 / n-Ga2O3 heterojunction and simulate a self-aligned top interdigitated coplanar PIN heterojunction solar-blind detector. The structural parameters were optimized based on the simulation results. By adjusting the width and spacing of the top interdigitated electrodes (8), as well as the distance between the electron-hole collectors, the device's IV characteristics, on-off ratio, and the spatial distribution of the heterojunction's built-in electric field were determined. This provided technical insights and specific parameters for heterojunction thin film growth, modulation doping, and device micro-nano fabrication.

[0075] A diamond / Ga2O3 heterojunction solar-blind detector was fabricated using methods including ion implantation, photolithography, wet etching, and ICP dry etching. First, a patterned Ga2O3 heterojunction photosensitive region was prepared. Next, an insulating dielectric isolation layer was sputtered, diamond electrodes 3 were patterned, and B ion implantation and contact electrodes were completed. Finally, the top interdigitated Ga2O3 electron collector was fabricated.

[0076] Using a comprehensive semiconductor device testing system, the IV electrical performance, transport characteristics, device switching ratio, and high-frequency response of the p-diamond / i-Ga2O3 / n-Ga2O3 heterojunction solar-blind detector were studied; the photoresponse spectrum of the device at different light wavelengths and luminous fluxes was analyzed; the internal mechanisms affecting the device's stress stability, high-temperature stability, and particle irradiation aging were explored, and optimization paths and solutions were provided to iterate the original solution.

[0077] Based on the principle of progressive scanning in matrix displays, a two-dimensional integrated array of diamond / Ga2O3 heterojunction solar-blind detectors was constructed. Individual detector units were integrated with active matrix driver units to create a complete single pixel. The impact of temperature and lighting conditions on the stability of the integrated device was analyzed. The integration technology for diamond heterojunction thin film devices was optimized. The two-dimensional integrated array of the developed diamond / Ga2O3 heterojunction photodetector chips was packaged and applied to ultraviolet solar-blind light signal detection and measurement, verifying the device parameters.

[0078] Finally, the production of high-performance self-powered diamond-based heterojunction solar-blind detector was completed.

[0079] In this embodiment, in order to overcome the bottleneck of diamond heterojunction growth, the interface polarity control technology is used to match the Ga growth surface with the diamond interface, thereby suppressing the interface defects caused by the O polar surface. In response to the problem of n-type doping of ultra-wide bandgap β-Ga2O3, an innovative periodic δ-type modulation doping technology is proposed to reduce the donor ionization energy to obtain a high concentration of electrons to suppress the generation of point defects. The heterojunction detector constructed with diamond and Ga2O3 will have the advantages of self-powered, low dark current, high signal-to-noise ratio, and high UV / visible suppression ratio. At the same time, the integrated diamond-based two-dimensional detector array chip has excellent photothermal stress and radiation stability, promoting the development of a new generation of on-chip integrated UV detection technology.

[0080] Obviously, the above embodiments of the present invention are merely examples for the purpose of illustrating the present invention, and are not intended to limit the embodiments of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A high-performance self-powered diamond-based heterojunction solar-blind detector, characterized by: The detector comprises, from bottom to top, a diamond single crystal substrate (1), a p-type diamond film (2), a Ga polarity control layer (4), an intrinsic i-Ga2O3 light absorption layer (5), a delta modulation doping layer (6), an AlO dielectric layer (7) and a top interdigitated electrode (8); The cross-sectional length of the diamond single crystal substrate (1) is consistent with the cross-sectional length of the p-type diamond film (2); The cross-sectional lengths of the Ga polarity control layer (4), the intrinsic i-Ga2O3 light absorption layer (5), the δ modulation doping layer (6), and the AlO dielectric layer (7) are all the same; Furthermore, the cross-sectional length of the Ga polarity control layer (4) is smaller than the cross-sectional length of the p-type diamond film (2); The Ga polarity control layer (4), the intrinsic i-Ga2O3 light absorption layer (5), the δ modulation doping layer (6), and the AlO dielectric layer (7) are arranged in the middle of the p-type diamond film (2); Two diamond electrodes (3) are provided on the p-type diamond film (2); the diamond electrodes (3) are located on both sides of the Ga polarity control layer (4); The top interdigitated electrode (8) is embedded in the interior of the AlO dielectric layer (7); The δ modulation doping layer (6) adopts periodic δ-type modulation doping technology to perform n-type Ga2O3 doping to obtain high-concentration carriers; By using MBE for atomic-level control, i-Ga2O3 / Sn:Ga2O3 modulation-doped superlattice was grown on the intrinsic i-Ga2O3 light absorption layer to obtain the δ modulation-doped layer (6).

2. The high-performance self-powered diamond-based heterojunction solar-blind detector according to claim 1, characterized in that: The top interdigitated electrode (8) comprises a first electrode structure (801) having a rectangular cross-section, and a second electrode structure arranged below the first electrode structure (801); the cross-section of the second electrode structure is a trapezoid; Wherein, the first electrode structure (801) is arranged on top of the AlO dielectric layer (7); The second electrode structure is embedded in the interior of the AlO dielectric layer (7); the second electrode structure is embedded in a relatively long first bottom surface connected to the bottom of the first electrode structure (801); and the second electrode structure is embedded in a relatively short second bottom surface connected to the top of the δ modulation doping layer (6).

3. The high-performance self-powered diamond-based heterojunction solar-blind detector according to claim 2, characterized in that: There are at least two top interdigitated electrodes (8).

4. The high-performance self-powered diamond-based heterojunction solar-blind detector according to claim 1, characterized in that: The p-type diamond film (2) is grown on a diamond single crystal substrate (1) using MPCVD, using borane BH3 as a doping source to grow the B-doped p-type diamond film (2).

5. The high-performance self-powered diamond-based heterojunction solar-blind detector according to claim 1, characterized in that: The Ga polarity control layer (4), the intrinsic i-Ga2O3 light absorption layer (5), and the delta modulation doping layer (6) are all grown sequentially from bottom to top on the p-type diamond film (2) using radio frequency MBE.

6. The high-performance self-powered diamond-based heterojunction solar-blind detector according to claim 1, characterized in that: The top interdigitated electrode (8) and the delta modulation doping layer (6) constitute a top interdigitated Ga2O3 electron collector; The p-type diamond film (2) serves as a diamond hole collector for photogenerated carriers.

7. The high-performance self-powered diamond-based heterojunction solar-blind detector according to claim 6, characterized in that: The diamond electrode (3) is completed by constructing a heavily doped ohmic contact region in a p-diamond hole collector with a low B concentration using ion implantation.

8. The high-performance self-powered diamond-based heterojunction solar-blind detector according to claim 1, characterized in that: The top interdigitated electrodes (8) are integrated into a two-dimensional array to form a light detection chip, and a single detector unit is integrated with an active matrix driving unit to construct a complete single pixel.

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