Photoelectric detector based on nano 3D schottky junction and preparation method thereof

Abstract

The application discloses a kind of photoelectric detector based on nano 3D schottky junction and preparation method thereof, it is related to semiconductor technical field, the method comprises: step 1, on the surface of cleaned substrate, depositing metal film;Step 2, the annealing of substrate under vacuum or protective atmosphere, so that the metal film deposited on the surface of substrate self-assembly growth is arrayed by metal nanoparticles;Step 3, the substrate is placed in vacuum or protective atmosphere and is kept warm, the temperature is not less than 900 DEG C and the time is not less than 40 min, and metal nanoparticles are induced to etch substrate, so that metal nano 3D schottky junction is obtained;Step 4, the physical vapor deposition method including sputtering, pulsed laser deposition or evaporation is used to continue depositing metal on substrate, and photoelectric detector is prepared.The method provided by the application is simple, low in cost, simple in steps, can be integrated into semiconductor processing flow, and can greatly improve the performance of photoelectric detector.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a photodetector based on a nano-3D Schottky junction and its fabrication method. Background Technology

[0002] In plasmonic hot-carrier photodetectors, Schottky junctions formed between metal and semiconductors are the primary means of collecting hot carriers. 3D Schottky junctions can overcome the limitations of 2D planar Schottky junctions by increasing the Schottky contact area, thereby improving hot carrier collection efficiency. Currently, the fabrication of 3D Schottky junctions has been achieved at the micrometer scale using patterning techniques; however, the hot carrier transport efficiency of micrometer-scale plasmonic materials remains too low. At the nanometer scale, the fabrication and application of 3D Schottky junctions are hampered by the complexity of patterning processes such as photolithography.

[0003] Therefore, those skilled in the art are dedicated to developing a new photodetector based on 3D Schottky junctions and its fabrication method to solve the difficulties in fabricating nano-3D Schottky junctions. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to overcome the difficulties in the preparation of nano 3D Schottky junctions.

[0005] To achieve the above objectives, the present invention provides an efficient fabrication method for a nano-3D Schottky junction array that is compatible with semiconductor processes, and on this basis, obtains a plasmonic photodetector with enhanced performance.

[0006] This invention provides a method for fabricating a photodetector based on a nano-3D Schottky junction, comprising the following steps: Step 1: Deposit a thin metal film on the surface of the cleaned substrate; Step 2: Anneal the substrate under vacuum or a protective atmosphere, so that the metal thin film deposited on the surface of the substrate self-assembles and grows into an array of metal nanoparticles. Step 3: Place the substrate in a vacuum or protective atmosphere and keep it at a temperature of not less than 900°C for not less than 40 minutes to induce the metal nanoparticles to etch the substrate, thereby obtaining a metal nano 3D Schottky junction; Step 4: Continue to deposit metal on the substrate using physical vapor deposition methods including sputtering, pulsed laser deposition, or evaporation to prepare the photodetector.

[0007] Furthermore, the substrate in step 1 is a semiconductor or a nitride.

[0008] Furthermore, the metal thin film in step 1 is a metal or alloy thin film, specifically one or more of Au, Ag, Cu, Al, In, Pt, and Pd.

[0009] Furthermore, in step 1, a physical vapor deposition method, including sputtering, pulsed laser deposition, or evaporation, is used to deposit the metal thin film on the surface of the substrate.

[0010] Further, step 1 includes the following sub-steps: Step 1.1: Place the cleaned substrate on the sample stage of the ion sputtering device, and then place the metal target on the target stage; Step 1.2: Close the sputtering chamber cover and evacuate the vacuum to approximately 0.01 to 30 Pa, and set the ionization current to 0.1 to 20 mA; Step 1.3: Apply voltage to the electrodes of the ion sputtering device, and after the current stabilizes, deposit a metal element or alloy onto the substrate; the thickness of the metal thin film is 1 nm to 200 nm.

[0011] Furthermore, step 2 includes the following sub-steps: Step 2.1: Transfer the substrate with the deposited metal film into the annealing furnace, seal it, and then evacuate the chamber of the annealing furnace to 10°C. -1 The temperature of the substrate is raised to not less than 850°C at a heating rate of 6°C / s; the vacuum pump operates continuously during the heating process. Step 2.2: After holding at the temperature for 300 seconds, heating is stopped. After cooling under vacuum to no higher than 150°C, air is introduced into the chamber of the annealing furnace to reduce atmospheric pressure and then cooled to room temperature, so that the metal film self-assembles and grows into an array composed of the metal nanoparticles.

[0012] Furthermore, step 3 includes the following sub-steps: Step 3.1: Place the substrate containing the array of metal nanoparticles into a tube furnace, and evacuate the chamber of the tube furnace to 10°C. -4 Below Pa; Step 3.2: Set the heating temperature to not less than 900℃ and maintain the temperature in a vacuum environment for not less than 40 minutes to induce the metal nanoparticles to etch the substrate and obtain the metal nano 3D Schottky junction.

[0013] Furthermore, step 4 includes the following sub-steps: Step 4.1: Place the substrate on the sample stage of the ion sputtering device, cover it with a mask, and then place the metal target on the target stage; Step 4.2: Close the sputtering chamber cover and evacuate the vacuum to approximately 10 Pa, and set the ionization current to 3 mA; Step 4.3: Apply voltage to the electrodes of the ion sputtering device. After the current stabilizes, deposit the metal element or alloy onto the substrate at a rate of 2 Å / s. Control the deposition time of the metal or alloy to be no less than 500 s to obtain the photodetector with a thickness of no less than 100 nm.

[0014] Furthermore, prior to step 1, the substrate surface is cleaned, including immersing the substrate in acetone for ultrasonic cleaning for 15 minutes, ultrasonic cleaning with ethanol for 10 minutes to remove surface impurities, rinsing with deionized water for 45 seconds, and then drying with nitrogen to remove residual moisture.

[0015] The present invention also provides a photodetector based on a nano 3D Schottky junction, comprising the photodetector prepared by the method for preparing a photodetector based on a nano 3D Schottky junction as described in any one of claims 1 to 9.

[0016] The photodetector based on a nano-3D Schottky junction and its fabrication method provided by this invention have at least the following technical advantages: 1. The preparation method provided by this invention is simple, can be integrated into the semiconductor processing flow, and significantly improves the performance of the photodetector; 2. The fabrication method provided by this invention fully utilizes the phenomenon of high-temperature induced thermal etching of the substrate by metal nanoparticles, generally forming a 3D embedded Schottky junction structure. Compared with the complexity of other nanoscale photolithography processes, this method is low-cost and simple, realizing the fabrication of a simple 3D Schottky junction photodetector, and has broad application prospects.

[0017] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0018] Figure 1 This is a preferred embodiment of the present invention, showing an array of Au nanoparticles formed on a GaN substrate; Figure 2 yes Figure 1 Cross-sectional scanning electron microscope image of the Au-GaN Schottky junction of the illustrated embodiment. Detailed Implementation

[0019] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0020] The technical solution adopted in this invention includes: 1. Substrate surface pretreatment: The substrate material can be semiconductor, nitride, or other materials. First, clean the substrate surface according to standard surface cleaning procedures.

[0021] 2. Surface Metal Thin Film Deposition: The metal or alloy thin film (one or more of Au, Ag, Cu, Al, In, Pt, and Pd) in this invention is deposited on the substrate surface using physical vapor deposition methods including sputtering, pulsed laser deposition, and evaporation. The thickness of the metal or alloy thin film is controlled between 0.5 and 200 nm.

[0022] 3. Preparation of metal nanoparticle arrays: Annealing of deposited metal or alloy films under vacuum or protective atmosphere allows them to self-assemble and grow into nanoparticle arrays.

[0023] 4. Heating-induced etching: The substrate with metal nanoparticles is placed in a vacuum environment or a protective atmosphere and kept at a high temperature for a long time.

[0024] 5. Photodetector fabrication: Electrodes are fabricated on a substrate after thermal induction etching of metal nanoparticles using physical vapor deposition methods including sputtering, pulsed laser deposition, and evaporation.

[0025] Example 1 This invention provides a method for fabricating a photodetector based on a nano-3D Schottky junction, comprising the following steps: Step 1: Deposit a thin metal film on the surface of the cleaned substrate; Step 2: Anneal the substrate under vacuum or a protective atmosphere so that the metal thin film deposited on the surface of the substrate self-assembles and grows into an array of metal nanoparticles. Step 3: Place the substrate in a vacuum or protective atmosphere and keep it at a temperature of not less than 900°C for not less than 40 minutes to induce metal nanoparticles to etch the substrate, thereby obtaining a metal nano 3D Schottky junction. Step 4: Continue to deposit metal on the substrate using physical vapor deposition methods, including sputtering, pulsed laser deposition, or evaporation, to prepare a photodetector.

[0026] Specifically, the substrate in step 1 is a semiconductor or a nitride.

[0027] Specifically, the metal thin film in step 1 is a metal or alloy thin film, specifically one or more of Au, Ag, Cu, Al, In, Pt and Pd.

[0028] Specifically, in step 1, a metal thin film is deposited on the surface of the substrate using physical vapor deposition methods, including sputtering, pulsed laser deposition, or evaporation.

[0029] Example 2 Based on Example 1, step 1 includes the following sub-steps: Step 1.1: Place the cleaned substrate on the sample stage of the ion sputtering device, and then place the metal target on the target stage; Step 1.2: Close the sputtering chamber cover and evacuate the vacuum to approximately 0.01 to 30 Pa, and set the ionization current to 0.1 to 20 mA; Step 1.3: Apply voltage to the electrodes of the ion sputtering device, and after the current stabilizes, deposit the metal element or alloy onto the substrate; the thickness of the metal thin film is 1nm~200nm.

[0030] Example 3 Based on Examples 1 and 2, step 2 includes the following sub-steps: Step 2.1: Transfer the substrate with the deposited metal film into the annealing furnace, seal it, and then evacuate the chamber of the annealing furnace to 10°C. -1 The temperature of the substrate is raised to no less than 850°C at a heating rate of 6°C / s, with the vacuum pump operating continuously during the heating process. Step 2.2: After holding at this temperature for 300 seconds, heating is stopped. After cooling under vacuum to a temperature not exceeding 150°C, air is introduced into the annealing furnace chamber to reduce atmospheric pressure, and the chamber is cooled to room temperature, allowing the metal film to self-assemble and grow into an array composed of metal nanoparticles.

[0031] Example 4 Based on Examples 1, 2, and 3, step 3 includes the following sub-steps: Step 3.1: Place the substrate containing the array of metal nanoparticles into a tube furnace, and evacuate the chamber of the tube furnace to 10°C. -4 Below Pa; Step 3.2: Set the heating temperature to no less than 900℃ and maintain the temperature in a vacuum environment for no less than 40 minutes to induce the metal nanoparticles to etch the substrate and obtain the metal nano 3D Schottky junction.

[0032] Example 5 Based on Examples 1, 2, 3, and 4, step 4 includes the following sub-steps: Step 4.1: Place the substrate on the sample stage of the ion sputtering apparatus, cover it with the mask, and then place the metal target on the target stage; Step 4.2: Close the sputtering chamber cover and evacuate the vacuum to approximately 10 Pa, and set the ionization current to 3 mA; Step 4.3: Apply voltage to the electrodes of the ion sputtering device. After the current stabilizes, deposit the metal element or alloy onto the substrate at a rate of 2 Å / s. Control the deposition time of the metal or alloy to be no less than 500 s to obtain a photodetector with a thickness of no less than 100 nm.

[0033] Example 6 Based on Examples 1, 2, 3, 4 and 5, before step 1, the substrate surface is cleaned, including immersing the substrate in acetone for ultrasonic cleaning for 15 minutes, ultrasonic cleaning with ethanol for 10 minutes to remove surface impurities, rinsing with deionized water for 45 seconds, and drying the residual moisture with nitrogen.

[0034] Example 7 The n-type gallium nitride substrate was ultrasonically cleaned with acetone for 15 minutes and then ultrasonically cleaned with ethanol for 10 minutes to remove surface impurities. After rinsing with deionized water for 45 seconds, residual moisture was dried with nitrogen gas.

[0035] The cleaned n-type gallium nitride substrate was placed on the sample stage of the ion sputtering apparatus, and then the Au metal target was placed on the target stage. The sputtering chamber cover was closed and the vacuum was evacuated to approximately 10 Pa. The ionization current was set to 3 mA, and a voltage was applied to the electrodes of the ion sputtering apparatus. After the current stabilized, Au was deposited on the n-type gallium nitride substrate at a rate of 2 Å / s. The Au deposition time was controlled to be 50 s, resulting in a 10 nm thick Au film.

[0036] An n-type gallium nitride substrate with deposited Au thin film is transferred into a rapid annealing furnace, sealed, and the chamber is evacuated to 10 °C. -1 Below Pa, the temperature of the n-type gallium nitride substrate was raised to 850℃ at a heating rate of 6℃ / s, with the vacuum pump running continuously during the heating process. After holding at this temperature for 300s, heating was stopped, and the substrate was cooled to 150℃ under vacuum. Air was then introduced into the heating chamber to reduce the atmospheric pressure, and the substrate was cooled to room temperature. The resulting Au nanoparticle array is shown below... Figure 1 As shown.

[0037] An n-type gallium nitride substrate loaded with Au nanoparticles was placed inside a tube furnace, and the chamber was evacuated to 10°C. -4 Below Pa.

[0038] The heating temperature was set to 900℃, and the temperature was maintained in a vacuum environment for 40 minutes to obtain an Au-GaN Schottky contact with a 3D embedded structure (e.g., ...). Figure 2 (As shown).

[0039] An n-type gallium nitride substrate loaded with Au nanoparticles, after being incubated at room temperature, was placed on the sample stage of an ion sputtering apparatus. A mask was then placed over the substrate, and an Au metal target was placed on the target stage. The sputtering chamber cover was closed, and the vacuum was evacuated to approximately 10 Pa. An ionization current of 3 mA was set, and a voltage was applied to the electrodes of the ion sputtering apparatus. After the current stabilized, Au was deposited onto the substrate at a rate of 2 Å / s. The Au deposition time was controlled to be 500 s, resulting in an Au electrode with a thickness of 100 nm.

[0040] Example 8 The p-type gallium nitride substrate was ultrasonically cleaned with acetone for 15 minutes and then ultrasonically cleaned with ethanol for 10 minutes to remove surface impurities. After rinsing with deionized water for 45 seconds, residual moisture was dried with nitrogen gas.

[0041] The cleaned p-type gallium nitride (GaN) substrate was placed on the sample stage of the ion sputtering apparatus, and then the Au metal target was placed on the target stage. The sputtering chamber cover was closed and the vacuum was evacuated to approximately 10 Pa. The ionization current was set to 3 mA, and a voltage was applied to the electrodes of the ion sputtering apparatus. After the current stabilized, Au was deposited on the p-type GaN substrate at a rate of 2 Å / s. The Au deposition time was controlled to be 50 s, resulting in a 10 nm thick Au film.

[0042] The p-type gallium nitride substrate with deposited Au thin film was transferred into a rapid annealing furnace, sealed, and the chamber was evacuated to 10 °C. -1 The temperature of a p-type gallium nitride substrate was increased to 850°C at a heating rate of 6°C / s below Pa, with the vacuum pump operating continuously during the heating process. After holding at this temperature for 300s, the heating was stopped, and the substrate was cooled to 150°C under vacuum. Then, air was introduced into the heating chamber to reduce the atmospheric pressure, and the substrate was cooled to room temperature to obtain Au nanoparticles.

[0043] A p-type gallium nitride substrate loaded with Au nanoparticles was placed in a tube furnace, and the chamber was evacuated to 10°C. -4 Below Pa.

[0044] The heating temperature was set to 900℃ and held in a vacuum environment for 40 minutes to obtain an Au-GaN Schottky contact with a 3D embedded structure.

[0045] A p-type gallium nitride substrate loaded with Au nanoparticles, after being incubated at room temperature, was placed on the sample stage of an ion sputtering apparatus. A mask was then placed over the substrate, and an Au metal target was placed on the target stage. The sputtering chamber cover was closed, and the vacuum was evacuated to approximately 10 Pa. An ionization current of 3 mA was set, and a voltage was applied to the electrodes of the ion sputtering apparatus. After the current stabilized, Au was deposited onto the substrate at a rate of 2 Å / s. The Au deposition time was controlled to be 500 s, resulting in a 100 nm thick Au electrode.

[0046] Example 9 The n-type gallium nitride substrate was ultrasonically cleaned with acetone for 15 minutes and then ultrasonically cleaned with ethanol for 10 minutes to remove surface impurities. After rinsing with deionized water for 45 seconds, residual moisture was dried with nitrogen gas.

[0047] The cleaned n-type gallium nitride substrate was placed on the sample stage of the ion sputtering apparatus, and then the Pd metal target was placed on the target stage. The sputtering chamber cover was closed and the vacuum was evacuated to approximately 10 Pa. The ionization current was set to 3 mA, and a voltage was applied to the electrodes of the ion sputtering apparatus. After the current stabilized, Pd was deposited on the n-type gallium nitride substrate at a rate of 2 Å / s. The Pd deposition time was controlled to be 100 s, resulting in a 15 nm thick Pd film.

[0048] The n-type gallium nitride substrate with deposited Pd thin film was transferred into a rapid annealing furnace, sealed, and the chamber was evacuated to 10 °C. -1 The temperature of an n-type gallium nitride substrate was raised to 850°C at a heating rate of 6°C / s below Pa, with the vacuum pump operating continuously during the heating process. After holding at this temperature for 300s, the heating was stopped, and the substrate was cooled to 150°C under vacuum. Then, air was introduced into the heating chamber to reduce the atmospheric pressure, and the substrate was cooled to room temperature to obtain Pd nanoparticles.

[0049] An n-type gallium nitride substrate loaded with Pd nanoparticles was placed in a tube furnace, and the chamber was evacuated to 10°C. -4 Below Pa.

[0050] The heating temperature was set to 900℃ and held in a vacuum environment for 40 minutes to obtain a Pd-GaN Schottky contact with a 3D embedded structure.

[0051] An n-type gallium nitride substrate containing Pd nanoparticles, after being incubated at room temperature, was placed on the sample stage of an ion sputtering apparatus. A mask was then placed over the substrate, and a Pd metal target was placed on the target stage. The sputtering chamber cover was closed, and the vacuum was evacuated to approximately 10 Pa. An ionization current of 3 mA was set, and a voltage was applied to the electrodes of the ion sputtering apparatus. After the current stabilized, Pd was deposited onto the substrate at a rate of 2 Å / s. The Pd deposition time was controlled to be 500 s, resulting in a 100 nm thick Pd electrode.

[0052] Example 10 The present invention also provides a photodetector based on a nano 3D Schottky junction, which is prepared by any one of the photodetector preparation methods based on a nano 3D Schottky junction in Examples 1 to 9.

[0053] Example 11 Based on Example 10, the present invention provides a photodetector based on a nano 3D Schottky junction in which the nano metal particles used form a 3D Schottky junction with the semiconductor substrate.

[0054] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for fabricating a photodetector based on a nano-3D Schottky junction, characterized in that, The method includes the following steps: Step 1: Deposit a metal thin film on the surface of a cleaned substrate, wherein the substrate is a semiconductor material and the metal thin film is a metal element or an alloy thin film. Step 2: Anneal the substrate under vacuum or a protective atmosphere, so that the metal thin film deposited on the surface of the substrate self-assembles and grows into an array of metal nanoparticles. Step 3: Place the substrate under vacuum for heat preservation to induce the metal nanoparticles to etch the substrate, thereby obtaining a metal nano 3D Schottky junction. Step 3 specifically includes the following sub-steps: Step 3.1: Place the substrate containing the array of metal nanoparticles into a tube furnace, and evacuate the chamber of the tube furnace to 10°C. -4 Below Pa, Step 3.2: Set the heating temperature to no less than 900℃ and maintain it in a vacuum environment for no less than 40 minutes to induce the metal nanoparticles to etch the substrate and obtain the metal nano 3D Schottky junction. Step 4: Continue to deposit metal on the substrate using physical vapor deposition methods such as sputtering, pulsed laser deposition, or evaporation to prepare the photodetector.

2. The method for fabricating a photodetector based on a nano-3D Schottky junction as described in claim 1, characterized in that, The metal element or alloy film in step 1 is one or more of Au, Ag, Cu, Al, In, Pt and Pd.

3. The method for fabricating a photodetector based on a nano-3D Schottky junction as described in claim 1, characterized in that, In step 1, the metal thin film is deposited on the surface of the substrate using a physical vapor deposition method such as sputtering, pulsed laser deposition, or evaporation.

4. The method for fabricating a photodetector based on a nano-3D Schottky junction as described in claim 3, characterized in that, Step 1 includes the following sub-steps: Step 1.1: Place the cleaned substrate on the sample stage of the ion sputtering device, and then place the metal target on the target stage; Step 1.2: Close the sputtering chamber cover and evacuate the vacuum to 0.01 to 30 Pa, and set the ionization current to 0.1 to 20 mA; Step 1.3: Apply voltage to the electrodes of the ion sputtering device, and after the current stabilizes, deposit a metal element or alloy onto the substrate; the thickness of the metal thin film is 1 nm to 200 nm.

5. The method for fabricating a photodetector based on a nano-3D Schottky junction as described in claim 1, characterized in that, Step 2 includes the following sub-steps: Step 2.1: The substrate with the deposited metal film is transferred into an annealing furnace. After sealing, the chamber of the annealing furnace is evacuated to below 10 Pa, and the temperature of the substrate is raised to not less than 800°C at a heating rate of 6°C / s. The vacuum pump continues to operate during the heating process. Step 2.2: After holding at the temperature for 300 seconds, heating is stopped. After cooling under vacuum to no higher than 150°C, air is introduced into the chamber of the annealing furnace to reduce atmospheric pressure and then cooled to room temperature, so that the metal film self-assembles and grows into an array composed of the metal nanoparticles.

6. The method for fabricating a photodetector based on a nano-3D Schottky junction as described in claim 4, characterized in that, Step 4 includes the following sub-steps: Step 4.1: Place the substrate on the sample stage of the ion sputtering device, cover it with a mask, and then place the metal target on the target stage; Step 4.2: Close the sputtering chamber cover and evacuate the vacuum to 10 Pa, and set the ionization current to 3 mA; Step 4.3: Apply voltage to the electrodes of the ion sputtering device. After the current stabilizes, deposit the metal element or alloy onto the substrate at a rate of 2 Å / s. Control the deposition time of the metal or alloy to be no less than 500 s to obtain the photodetector with a thickness of no less than 100 nm.

7. The method for fabricating a photodetector based on a nano-3D Schottky junction as described in claim 1, characterized in that, Before step 1, the substrate surface is cleaned, including immersing the substrate in acetone for ultrasonic cleaning for 15 minutes, ultrasonic cleaning with ethanol for 10 minutes to remove surface impurities, rinsing with deionized water for 45 seconds, and drying with nitrogen to remove residual moisture.

8. A photodetector based on a nano-3D Schottky junction, characterized in that, The photodetector includes the photodetector prepared by the method for preparing a photodetector based on a nano 3D Schottky junction as described in any one of claims 1 to 7.

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