Gate-controlled high-response Sn-doped Ga2O3 micron-wire photodetector and its preparation method

Abstract

This invention proposes a gate-controlled, high-response Sn-doped Ga2O3 micron-wire photodetector and a method for fabricating it. The photodetector comprises a substrate on which, from bottom to top, a Sn-doped Ga2O3 micron-wire layer, an insulating layer, and a gate are arranged. A source electrode is provided on the substrate on one side of the Sn-doped Ga2O3 micron-wire layer, and a drain electrode is provided on the substrate on the other side. This invention utilizes a gate voltage to control photogenerated holes, thereby altering the Schottky barrier, thereby fabricating a highly responsive Sn-doped Ga2O3 micron-wire photodetector.

Description

Technical Field

[0001] The present invention relates to the technical field of photodetectors, and in particular to a gate-controlled high-response Sn-doped Ga2O3 micron-wire photodetector and a preparation method thereof. Background Art

[0002] Ga2O3, an ultra-wide bandgap semiconductor with a bandgap of 4.2-5.3 eV, exhibits intrinsic solar-blind selectivity, high breakdown field strength, resistance to radiation damage, and excellent stability, making it suitable for photodetection devices. Various electronic and optoelectronic devices based on Ga2O3 have been reported. Conventional high-response Ga2O3 photodetectors are mostly fabricated using undoped Ga2O3, with their high response derived from photoconductivity and the avalanche effect of photodiodes. Currently, detectors fabricated using Sn-doped Ga2O3 materials suffer from high dark current, low light-to-dark current ratio, and low responsivity. Summary of the Invention

[0003] The present invention proposes a gate-controlled high-response Sn-doped Ga2O3 micron-wire photodetector and a preparation method thereof, which realizes the preparation of a high-response Sn-doped Ga2O3 micron-wire photodetector by regulating photogenerated holes through gate voltage to change the Schottky barrier.

[0004] The technical solution of the present invention is implemented as follows: a gate-controlled high-response Sn-doped Ga2O3 micron-wire photodetector includes a substrate, on which a Sn-doped Ga2O3 micron-wire layer, an insulating layer and a gate are arranged in sequence from bottom to top; a source is arranged on the substrate on one side of the Sn-doped Ga2O3 micron-wire layer, and a drain is arranged on the substrate on the other side.

[0005] Furthermore, the source and drain electrodes each include a Ti layer with a thickness of 50 to 100 nanometers, and a Au layer with a thickness of 40 to 90 nanometers is provided on the upper side of the Ti layer; the distance between the source and drain electrodes is 5 to 15 micrometers.

[0006] Furthermore, the gate includes a Ni layer with a thickness of 40 to 60 nanometers, and an Au layer with a thickness of 80 to 120 nanometers is provided on the upper side of the Ni layer; the gate has a length of 2 to 6 micrometers and a width of 0.8 to 5 micrometers.

[0007] Furthermore, the diameter of the Sn-doped Ga2O3 micrometer wire is 0.8 to 5 micrometers.

[0008] Furthermore, the insulating layer is an Al2O3 insulating layer; the substrate is an Al2O3 substrate, and the thickness of the substrate is 300 to 400 microns.

[0009] A method for preparing a gate-controlled high-response Sn-doped Ga2O3 micron-wire photodetector comprises the following steps:

[0010] (1) Sn-doped Ga2O3 micrometer wires were ultrasonically dispersed in anhydrous ethanol and then drop-coated on the substrate;

[0011] (2) annealing the substrate after the drop coating in step (1) in argon gas to obtain a Sn-doped Ga2O3 micron line layer;

[0012] (3) Spin-coating photoresist on the substrate of step (2) and preparing source and drain patterns using laser direct write lithography technology, wherein the source and drain patterns are respectively located on both sides of the Sn-doped Ga2O3 micron line layer;

[0013] (4) Prepare the source and drain electrodes using magnetron sputtering technology and perform lift-off process;

[0014] (5) an insulating layer is prepared on the Sn-doped Ga2O3 micron-line layer between the source and drain electrodes using atomic layer deposition technology;

[0015] (6) Spin-coating a photoresist on the substrate of step (5) and preparing a gate pattern using laser direct writing lithography technology, wherein the gate pattern is located on the insulating layer;

[0016] (7) The gate is prepared using thermal evaporation technology and peeled off using the lift-off process.

[0017] Furthermore, in step (2), the substrate after drop coating is annealed at 400-600° C. for 5-10 minutes.

[0018] Furthermore, in step (3), the photolithography development time is 40-60 seconds.

[0019] Furthermore, in step (5), the aluminum source used for atomic layer deposition is trimethylaluminum, the oxygen source is water, and the gas is argon; the atomic layer deposition steps are as follows: before deposition, the pressure of the deposition chamber is pumped down to less than 2.0×10 -3 Pa; the temperature is increased to 250°C, and then argon is introduced, and the gas pressure is adjusted to 1.2~1.8Pa. The pulse times of the aluminum source and oxygen source are 0.025~0.035 seconds and 0.015~0.025 seconds respectively, the purge time is 40 seconds and 30 seconds respectively, the deposition time is 200~700 minutes, and the deposition thickness is about 20~70 nanometers.

[0020] Furthermore, in step (6), the photolithography development time is 30 to 60 seconds.

[0021] Beneficial effects of the present invention:

[0022] Because Sn-doped Ga2O3 microwires adsorb oxygen on their surfaces, electrons are trapped on the microwire surface to form oxygen ions, creating a Schottky barrier between the electrode and the Ga2O3 microwire. This invention fabricates a top-gate Sn-doped Ga2O3 microwire photodetector on a substrate. In the dark state, applying a negative gate voltage reduces the device's dark current, achieving a large light-to-dark current ratio. In the presence of light, the gate voltage regulates the movement of photogenerated holes, reducing the height of the Schottky barrier between the electrode and the microwire, thereby achieving high responsivity in the Sn-doped Ga2O3 microwire. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 Schematic diagram of the structure of the device of the present invention.

[0025] Figure 2 This is a photo of the device described in Example 1 under an optical microscope.

[0026] Figure 3 This is a photograph of the device described in Example 2 under an optical microscope.

[0027] Figure 4 This is the XRD pattern of Sn-doped Ga2O3 microwires.

[0028] Figure 5 is the transfer characteristic curve of the device in the dark state.

[0029] Figure 6 The device is at an optical power of about 1μw / cm 2 Transfer characteristic curve under 254nm ultraviolet light irradiation.

[0030] Figure 7 It is the IT curve of the device at gate voltages of 0V and -15V.

[0031] Figure 8 The relationship between the device's responsivity and external quantum efficiency and gate voltage when the source-drain voltage is 30V. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] like Figure 1 As shown, the gate-regulated high-response Sn-doped Ga2O3 micron-wire photodetector includes a substrate, on which a Sn-doped Ga2O3 micron-wire layer, an insulating layer and a gate are arranged in sequence from bottom to top. A source is arranged on the substrate on one side of the Sn-doped Ga2O3 micron-wire layer, and a drain is arranged on the substrate on the other side.

[0035] The diameter of the Sn-doped Ga2O3 micrometer wire is 0.8 to 2 micrometers. The insulating layer is an Al2O3 insulating layer; the substrate is an Al2O3 substrate, and the thickness of the substrate is 300 to 400 micrometers.

[0036] Sn-doped Ga2O3 microwires were fabricated by ultrasonically cleaning a sapphire substrate in acetone, anhydrous ethanol, and deionized water for 15 minutes each, followed by drying with high-purity nitrogen. A 500nm thick gold film was deposited on the cleaned sapphire substrate using a magnetron sputtering system. The gold-coated sapphire substrate was then placed in a high-temperature tube furnace and rapidly annealed at 900°C. After annealing, the gold film on the sapphire aggregated into particles.

[0037] A powder mixture of gallium oxide, tin oxide, and carbon powder (mass ratio 1:1:2) was placed on an alumina boat, on which a sapphire / gold particle substrate was suspended. The alumina boat was then placed in a tube furnace. During the growth process, argon (200 sccm) and oxygen (5 sccm) were injected into the tube, and the tube was simultaneously evacuated using a mechanical pump (pumping rate = 4 L / s). The tube furnace was heated to 1160°C and held at this temperature for 1 hour. Finally, the furnace was cooled to room temperature.

[0038] A method for preparing a gate-controlled high-response Sn-doped Ga2O3 micron-wire photodetector comprises the following steps:

[0039] (1) The substrate was ultrasonically cleaned with acetone, anhydrous ethanol, and ultrapure water for 10 minutes each; Sn-doped Ga2O3 micron wires ultrasonically dispersed in anhydrous ethanol were drop-coated on the substrate, where the concentration of Sn-doped Ga2O3 micron wires was about 0.1 mg / ml;

[0040] (2) annealing the substrate after drop coating in step (1) at 400° C. in argon for 5 minutes;

[0041] (3) The steps of laser direct writing lithography are as follows: first, draw the required pattern with a source-drain spacing of 15 μm, then spin-coat the photoresist, heat it at 115°C for 2 minutes, and then place it in a laser direct writing lithography machine for exposure. After the exposure is completed, take it out and develop it to obtain the desired pattern;

[0042] (4) Titanium was sputtered using magnetron sputtering technology. The steps of magnetron sputtering were as follows: the developed sample was placed in the sputtering chamber. Before sputtering, the vacuum of the growth chamber was pumped to less than 2.0×10 -4 During the growth process, argon gas was introduced, and the gas flux was maintained at 10 sccm. The power of the entire sputtering process was 90 W, and the growth pressure was 2.5 Pa. Titanium was sputtered first, the sputtering time was 1 minute, and the sputtering thickness was about 50 nanometers; then gold was sputtered, the sputtering time was 2 minutes, and the sputtering thickness was about 90 nanometers.

[0043] (5) Atomic layer deposition (ALD) was used to grow Al2O3 on the surface of Sn-doped Ga2O3 micrometer wires. The aluminum source used in ALD was trimethylaluminum, the oxygen source was water, and the gas was argon. The ALD steps were as follows: Before deposition, the pressure of the deposition chamber was pumped down to below 2.0×10 -3 Pa; the temperature was increased to 250°C, and then argon gas was introduced, and the gas pressure was regulated to 1.2-1.8 Pa. The pulse times of the aluminum source and oxygen source were 0.025 seconds and 0.015 seconds, respectively. The purge times were 40 seconds and 30 seconds, respectively. The deposition time was 350 minutes, and the deposition thickness was about 35 nm.

[0044] (6) Using laser direct writing, a gate pattern was prepared in the same manner as in step (3), with a gate length of 5 μm and a width of 1 μm;

[0045] (7) Nickel-gold was deposited using thermal evaporation technology. The thermal evaporation steps were as follows: the developed sample was placed in the evaporation chamber. Before evaporation, the vacuum of the growth chamber was pumped to less than 2.0×10 -4 Pa, and the current was adjusted to 100 A. Nickel was evaporated first for 3 minutes to a thickness of approximately 50 nm. Gold was then evaporated for 5 minutes to a thickness of approximately 90 nm.

[0046] Figure 2 This is a photograph of the device described in Example 1 under an optical microscope, wherein the gate length is 5 microns, the width is 1 micron, and the source-drain spacing is 15 microns.

[0047] Example 2

[0048] This embodiment is substantially the same as the first embodiment, except that the method for preparing a gate-controlled high-response Sn-doped Ga2O3 micrometer-line photodetector comprises the following steps:

[0049] (1) Ultrasonic cleaning of the substrate with acetone, anhydrous ethanol, and ultrapure water for 10 minutes each; drop coating of Sn-doped Ga2O3 microwires ultrasonically dispersed in anhydrous ethanol on the substrate, wherein the concentration of Sn-doped Ga2O3 microwires is about 0.05 mg / ml;

[0050] (2) annealing the substrate after drop coating in step (1) at 400° C. in argon for 5 minutes;

[0051] (3) The steps of laser direct writing lithography are as follows: first, draw the required pattern with a source-drain spacing of 10 μm, then spin-coat the photoresist, heat it at 115°C for 2 minutes, and then place it in a laser direct writing lithography machine for exposure. After the exposure is completed, take it out and develop it to obtain the desired pattern;

[0052] (4) Titanium is sputtered using magnetron sputtering technology. The steps of magnetron sputtering are as follows: Place the developed sample into the sputtering chamber. Before sputtering, the vacuum of the growth chamber is pumped to less than 5.0×10 -4 During the growth process, argon gas was introduced, and the gas flux was maintained at 20 sccm. The power of the entire sputtering process was 50 W, and the growth pressure was 1.5 Pa. Titanium was sputtered first, the sputtering time was 1.5 minutes, and the sputtering thickness was about 70 nanometers; then gold was sputtered, the sputtering time was 1.5 minutes, and the sputtering thickness was about 80 nanometers.

[0053] (5) Atomic layer deposition (ALD) was used to grow Al2O3 on the surface of Sn-doped Ga2O3 micrometer wires. The aluminum source used in ALD was trimethylaluminum, the oxygen source was water, and the gas was argon. The ALD steps were as follows: Before deposition, the pressure of the deposition chamber was pumped down to below 2.0×10 -3 Pa; the temperature was increased to 200°C, and then argon gas was introduced, and the gas pressure was adjusted to 1.2-1.8 Pa. The pulse times of the aluminum source and oxygen source were 0.035 seconds and 0.025 seconds, respectively. The purge times were 40 seconds and 30 seconds, respectively. The deposition time was 500 minutes, and the deposition thickness was about 50 nm.

[0054] (6) Using laser direct writing, a gate pattern was prepared in the same manner as in step (3), with a gate length of 3 μm and a width of 4.5 μm;

[0055] (7) Nickel-gold was deposited using thermal evaporation technology. The thermal evaporation steps were as follows: the developed sample was placed in the evaporation chamber. Before evaporation, the vacuum of the growth chamber was pumped to less than 2.0×10 -4 Pa, the current was adjusted to 100 A, nickel was evaporated first, and then gold was evaporated, and the evaporation time was 10 minutes.

[0056] Figure 3This is a photograph of the device described in Example 2 under an optical microscope, wherein the gate length is 3 microns, the width is 4.5 microns, and the source-drain spacing is 10 microns.

[0057] Figure 4 This is the XRD of Sn-doped Ga2O3 microwires in Example 2.

[0058] Figure 5 The transfer characteristic curve of the device in Example 2 in the dark state, where the source-drain voltage is 10V and the switching ratio of the device in the dark state is about 10 5 .

[0059] Figure 6 The device in Example 1 has an optical power of about 1 μw / cm 2 The transfer characteristic curve under 254nm ultraviolet light irradiation shows that the on / off ratio of the device is about 10.

[0060] Figure 7 The IT curves of the device in Example 2 at gate voltages of 0V and -15V are shown. When the gate voltage is -15V, the dark current is significantly suppressed, and the light-to-dark current ratio is increased by 10% compared with the gate voltage of 0V. 5 .

[0061] Figure 8 The relationship between the responsivity and external quantum efficiency of the device in Example 1 and the gate voltage when the source-drain voltage is 30V is shown. The device responsivity can reach about 10 6 ~10 7 A / W, the external quantum efficiency can reach about 10 6 %~10 7 %.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gate-controlled, high-response Sn-doped Ga2O3 micrometer-wire photodetector, comprising a substrate, characterized in that: A Sn-doped Ga2O3 micron-line layer, an insulating layer, and a gate are sequentially arranged on the substrate from bottom to top. A source electrode is arranged on the substrate on one side of the Sn-doped Ga2O3 micron-line layer, and a drain electrode is arranged on the substrate on the other side. The source and drain electrodes each include a 50-100 nm thick Ti layer, with a 40-90 nm thick Au layer on top of the Ti layer; the spacing between the source and drain electrodes is 5-15 μm; The gate comprises a 40-60 nanometer thick Ni layer, with an 80-120 nanometer thick Au layer disposed on top of the Ni layer; the gate has a length of 2-8 micrometers and a width of 0.8-5 micrometers; The diameter of Sn-doped Ga2O3 micron wires is 0.8 to 5 microns; The insulating layer is an Al2O3 insulating layer; the substrate is an Al2O3 substrate, and the thickness of the substrate is 300 to 400 microns.

2. The method for preparing the gate-controlled high-response Sn-doped Ga2O3 micrometer-wire photodetector according to claim 1, characterized in that: The following steps are involved: (1) Sn-doped Ga2O3 micrometer wires were ultrasonically dispersed in anhydrous ethanol and then drop-coated on the substrate; (2) annealing the substrate after the drop coating in step (1) in argon gas to obtain a Sn-doped Ga2O3 micron line layer; (3) Spin-coating photoresist on the substrate of step (2) and preparing source and drain patterns using laser direct write lithography technology, wherein the source and drain patterns are respectively located on both sides of the Sn-doped Ga2O3 micron line layer; (4) Prepare the source and drain electrodes using magnetron sputtering technology and perform lift-off process; (5) an insulating layer is prepared on the Sn-doped Ga2O3 micron-line layer between the source and drain electrodes using atomic layer deposition technology; (6) Spin-coating a photoresist on the substrate of step (5) and preparing a gate pattern using laser direct writing lithography technology, wherein the gate pattern is located on the insulating layer; (7) The gate is prepared using thermal evaporation technology and peeled off using the lift-off process.

3. The preparation method according to claim 2, characterized in that In step (2), the substrate after drop coating is annealed at 400-600° C. for 5-10 minutes.

4. The preparation method according to claim 2, characterized in that In step (3), the photolithography development time is 40-60 seconds.

5. The preparation method according to claim 2, characterized in that In step (5), the aluminum source used for atomic layer deposition is trimethylaluminum, the oxygen source is water, and the gas is argon.

6. The preparation method according to claim 2, characterized in that In step (6), the photolithography development time is 30 to 60 seconds.

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