Resonant InGaN quantum well integrated micro-opto-electro-mechanical accelerometer device and preparation method thereof

Abstract

The invention discloses a resonant InGaN quantum well integrated micro-opto-electro-mechanical accelerometer device and a preparation method thereof, a silicon-based nitride wafer is used as a carrier, a silicon substrate layer, an aluminum nitride layer, a u-type gallium nitride layer, an n-type gallium nitride layer, an InGaN quantum well layer and a p-type gallium nitride layer are sequentially arranged from bottom to top, and a p-type electrode is arranged above the p-type gallium nitride layer. And an n-type electrode is arranged above the edge of the n-type gallium nitride layer. According to the invention, a resonant beam detector and a crescent LED which are different in shape are prepared on a nitride material on a silicon substrate by using a photoetching process and an ICP (Inductively Coupled Plasma) etching process, light emitted by the crescent LED is converged to a high-sensitivity resonant beam, and under an acceleration load, light current received by the resonant beam changes periodically, so that the sensitivity of the high-sensitivity resonant beam detector is improved, and the sensitivity of the high-sensitivity resonant beam detector is improved. The magnitude of the corresponding acceleration can be reversely deduced through the periodic resonant frequency, so that the detection device with the high-sensitivity long and straight resonant beam is enabled to generate oscillation, and the detection device is enabled to generate periodically changing current to sense the magnitude of the acceleration.

Description

Technical Field

[0001] The present invention belongs to the field of quantum electronics and optomechanical technology, and in particular relates to a resonant InGaN quantum well integrated micro-optomechanical accelerometer device and a preparation method thereof. Background Art

[0002] At present, most semiconductor materials have relatively simple functions, and are basically aimed at realizing a single function. Most of the LEDs on the market have relatively simple functions and cannot perform the above two actions at the same time. Therefore, in the present invention, the light-emitting function of the InGaN quantum well LED is integrated with the photoelectric detection function of the resonant beam detector, and the light source and the detection component are combined to prepare a resonant InGaN quantum well integrated micro-opto-electromechanical accelerometer system. The present invention prepares two LEDs and detectors of different shapes. In order to meet people's requirements for miniaturization, low cost and high sensitivity of acceleration sensors, the research on optical accelerometers has become a new hotspot. Optical acceleration sensors have the dual advantages of optical measurement and silicon-based micromachining. Based on optical principles, the displacement of the sensitive mass block under the action of acceleration will cause changes in optical properties such as interference and diffraction, and acceleration measurement is achieved by monitoring optical indicators. Since the optical means have high displacement measurement accuracy and are immune to circuit noise, optical accelerometers have extremely high sensitivity and resolution.

[0003] Therefore, the following technical problems exist: 1. For the design of the overall beam structure of the LED, it is necessary to consider whether the length and width of the resonant beam can cause it to produce obvious oscillations, whether the length of the beam of the light-emitting device can irradiate the light to the resonant beam of the detection device, and the feasibility of the actual processing and application process.

[0004] 2. Wet etching technology is a very important technology after the device is processed. When mixing hydrofluoric acid and dilute nitric acid to wet-etch silicon, make sure the beam is suspended.

[0005] 3. When designing the circuit connection of the device, it is necessary to ensure that the wiring position and wiring will not cause any interference to the normal operation of the device.

[0006] 4. The spacing between electrodes and the width of electrodes should be reasonable to prevent short circuit. Summary of the invention

[0007] In order to solve the above problems, the present invention discloses a resonant InGaN quantum well integrated micro-opto-electromechanical accelerometer device and its preparation method, and invents and prepares two LEDs and detectors of different shapes. In order to meet people's requirements for miniaturization, low cost and high sensitivity of acceleration sensors, the research on optical accelerometers has become a new hotspot. Optical acceleration sensors have the dual advantages of optical measurement and silicon-based micromachining. Based on optical principles, the displacement of the sensitive mass block under the action of acceleration will cause changes in optical properties such as interference and diffraction, and acceleration measurement is achieved by monitoring optical indicators. Since optical means have high displacement measurement accuracy and are immune to circuit noise, optical accelerometers have extremely high sensitivity and resolution.

[0008] A resonant InGaN quantum well micro-opto-electromechanical integrated accelerometer device comprises an LED beam light-emitting device and an LED beam detection device; wherein the LED beam detection device comprises a rectangular beam and two disks connected thereto, and the LED beam light-emitting device is a crescent-shaped beam and two disks connected thereto; wherein the length of the rectangular beam is greater than the length of the crescent-shaped beam, wherein the left and right ends of the crescent-shaped beam and the rectangular beam are respectively connected to the middle of the disks adjacent to the two sides thereof, wherein the disk on the left is a p-type electrode, and the disk on the right is an n-type electrode.

[0009] Furthermore, the length ratio of the rectangular beam to the crescent-shaped beam is 1.8:1.

[0010] A method for preparing a resonant InGaN quantum well micro-opto-mechanical-mechanical integrated accelerometer device, wherein the device uses a silicon-based nitride wafer as a carrier, and its structure from bottom to top is a silicon substrate layer, an aluminum nitride layer, a u-type gallium nitride layer, an n-type gallium nitride layer, an InGaN quantum well layer, and a p-type gallium nitride layer, wherein a p-type electrode is arranged above the p-type gallium nitride layer, and an n-type electrode is arranged above the edge of the n-type gallium nitride layer; wherein all structures above the exposed silicon substrate layer are etched away, a stepped table is etched at the edge of the n-type gallium nitride layer, the lower table of the stepped table is exposed, an n-type electrode is deposited on the lower table, and the n-type gallium nitride layer and the n-type electrode are exposed on the surface in a circular ring shape; The specific steps are as follows: The first step is to spin-coat a layer of photoresist on the surface of the p-type gallium nitride layer of the silicon-based gallium nitride wafer. Then, optical lithography is used to define two pairs of disks on the spin-coated photoresist, connected by a long, thin straight rectangular beam and a crescent-shaped beam. Step 2: depositing a layer of metal nickel with a thickness of 300 nm on the upper surface of the pattern defined in the first step by electron beam evaporation technology; then placing the wafer in an acetone solution for ultrasonic treatment; after the treatment, placing the wafer in ultrapure water and anhydrous ethanol in turn for cleaning, and then cleaning it again in ultrapure water; finally, removing the remaining photoresist, thereby obtaining a mask pattern of nickel; Step 3: At the edge of the silicon-based nitride wafer, the ICP etching technology is used to etch downward to the middle of the n-type gallium nitride layer, thereby successfully transferring the pattern defined in the first step to the n-type gallium nitride layer of the silicon-based nitride wafer, and obtaining the desired LED single resonant beam structure, which is a rectangular beam and a crescent beam respectively; Step 4: After completing the third step, use dilute nitric acid to remove the metal nickel deposited on the surface of the wafer, and then immediately put the wafer into ultrapure water for cleaning; Step 5: Spin-coat photoresist on the surface of each single resonant beam structure LED to prevent the beam structure from being etched away during the etching process, thus playing a protective role; Step 6: Deposit a 300nm thick layer of metal nickel on the defined pattern through electron beam evaporation technology; then, wash the epitaxial wafer in acetone solution, anhydrous ethanol, and ultrapure water in turn. Finally, remove the remaining photoresist to obtain a nickel mask pattern; Step 7: Using ICP etching technology, the pattern obtained in the sixth step is etched from the n-type gallium nitride layer downward to the surface of the silicon substrate layer, thereby transferring the pattern to the silicon substrate layer, and finally cleaning the residual photoresist; Step 8: By using electron beam evaporation technology, a positive electrode is evaporated on the p-type electrode area pattern on the p-type gallium nitride layer, and a negative electrode is evaporated on the n-type electrode area pattern on the n-type gallium nitride layer, and then the residual photoresist is cleaned to obtain a p-type electrode and an n-type electrode, both of which are disc-shaped; Step 9: Mix hydrofluoric acid and dilute nitric acid in a ratio of 1:10, and perform wet silicon etching to carve the silicon substrate layer into two silicon pillars and a bottom surface for supporting the structure, forming two suspended LED single beam structures.

[0011] Furthermore, the p-type electrode and the n-type electrode are both formed by Au / Ni evaporation.

[0012] Furthermore, the p-type electrode is deposited on the upper surface of the p-type gallium nitride layer.

[0013] In the present invention, when the LED with a crescent-shaped beam emits light, the light will converge on the high-sensitivity resonant beam. Under the acceleration load, the photocurrent received by the resonant beam will change periodically. Therefore, the corresponding acceleration size can be inferred through the periodic resonance frequency, causing the detection device with a long straight resonant beam with high sensitivity to oscillate, thereby generating a periodically changing current and sensing the acceleration size.

[0014] Beneficial effects: Compared with the prior art, the present invention has the following advantages: 1. The present invention integrates the two functions of light emission and detection into the same chip, without the need to use other chips. It has high practicality and simple structure. It can directly collect electrical signals and infer the corresponding acceleration size. It has high sensitivity and good conversion effect.

[0015] 2. The design of the short crescent-shaped beam facilitates the convergence of light onto the resonant beam for detection, which can effectively improve the accuracy and sensitivity of detection. The slender shape of the long straight resonant beam with high sensitivity is designed to produce a more obvious oscillation effect and to receive the light emitted by the crescent-shaped LED light-emitting device, obtain the periodic resonant frequency, and sense the magnitude of acceleration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : Schematic diagram of the structure of a resonant InGaN quantum well micro-opto-electromechanical integrated accelerometer (the upper part is the front view, and the lower part is the top view).

[0017] Figure 2 , one Process flow chart of a single LED in a resonant InGaN quantum well micro-opto-electromechanical integrated accelerometer device.

[0018] Figure 3 , one Light intensity diagram of a resonant InGaN quantum well micro-opto-electromechanical integrated accelerometer device based on COMSOL simulation software; Figure 4 :Far-field diagram of a resonant InGaN quantum well micro-opto-electromechanical integrated accelerometer device based on COMSOL simulation software.

[0019] The figure marks are: 1-silicon substrate layer, 2-aluminum nitride layer, 3-u-type gallium nitride layer, 4-n-type gallium nitride layer, 5-InGaN quantum well layer, 6-p-type gallium nitride layer, 7-p-type electrode, 8-n-type electrode; 9-rectangular beam; 10-crescent-shaped beam. DETAILED DESCRIPTION

[0020] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0021] like Figure 1 As shown, a resonant InGaN quantum well micro-opto-electromechanical integrated accelerometer device of the present embodiment includes an LED beam light-emitting device and an LED beam detection device; wherein the LED beam detection device includes a rectangular beam 9 and two disks connected thereto, and the LED beam light-emitting device is a crescent-shaped beam 10 and two disks connected thereto; wherein the length of the rectangular beam 9 is greater than the length of the crescent-shaped beam 10, wherein the left and right ends of the crescent-shaped beam 10 and the rectangular beam 9 are respectively connected to the middle of the disks adjacent to them on both sides, wherein the disk on the left is a p-type electrode 7, and the disk on the right is an n-type electrode 8.

[0022] The length ratio of the rectangular beam 9 to the crescent-shaped beam 10 is 1.8:1.

[0023] Among them, the structure above the silicon substrate layer exposed in the top view is completely etched away, leaving only the disk and the part below the beam connected to the disk. The exposed shape consists of two parts, one part is two identical disks and a rectangular resonant beam connected to them, and the other part is two identical disks and a shorter crescent-shaped beam connected to them.

[0024] Among them, the structures above the silicon substrate layer exposed in the top view are all etched away, leaving only the disk and the part below the beam connected to the disk. The exposed shape consists of two parts, one is two disks and a rectangular resonant beam, and the other is two disks and a shorter crescent-shaped beam. Among them, the long straight resonant beam with high sensitivity is 6μm wide and 400μm long in the side view; the short crescent-shaped beam is 20 to 30μm wide and 250μm long in the side view. The radius of the p-type electrode covering the p-type gallium nitride layer and the n-type electrode of the n-type gallium nitride layer are both 30μm, and the thickness of the two electrodes is 120nm.

[0025] Taking the preparation of a disk with a radius of 30 μm, a highly sensitive rectangular resonant beam with a width of 6 μm and a length of 400 μm in the side view, and a shorter crescent-shaped beam with a width of 20 to 30 μm and a length of 250 μm in the side view as an example, the preparation process is as follows: Step 1: After the silicon-based nitride wafer is ultrasonically cleaned in acetone solution, anhydrous ethanol and ultrapure water for five minutes, the silicon substrate gallium nitride wafer is blown dry with nitrogen. Then, a photoresist AZ-5214 is spin-coated on the p-type gallium nitride layer on the silicon-based nitride wafer at a speed of 4000 rpm. The spin coating time is 40 seconds and the photoresist thickness is 1.5μm. Then, using optical lithography technology, a long, thin, straight single-beam two-disc LED pattern and a shorter crescent-shaped single-beam two-disc LED pattern are defined on the spin-coated photoresist layer. The model of the photolithography machine used is MA6.

[0026] Step 2: Deposit a 300nm thick layer of metal nickel on the p-type gallium nitride layer through electron beam evaporation technology. Then clean it and remove the remaining photoresist to obtain a nickel mask pattern.

[0027] Step 3: Etch down to the middle of the n-type gallium nitride layer through ICP etching technology, so that the pattern defined in the first step can be successfully transferred to the n-type gallium nitride on the silicon-based nitride wafer to obtain the desired LED single beam structure.

[0028] After completing the third step, the metallic nickel deposited on the surface is removed using dilute nitric acid, and then the wafer is immediately placed in ultrapure water for cleaning.

[0029] Step 4: Start using the coating machine to spin-coat the photoresist AZ-5214 on the upper surface of the single beam structure at a speed of 4000 rpm. The spin coating time is 40 seconds and the photoresist thickness is 1.5 μm.

[0030] Step 5: Deposit a 300nm thick layer of nickel on the n-type gallium nitride layer using electron beam evaporation technology. Then clean it and remove the remaining photoresist.

[0031] Step 6: Using ICP etching technology, the pattern obtained in the fifth step is etched from the n-type gallium nitride layer downward to the surface of the silicon substrate layer, thereby transferring the pattern to the silicon substrate layer, and finally cleaning the remaining photoresist.

[0032] Step 7: By using electron beam evaporation technology, the positive electrode and the negative electrode are evaporated on the p-type electrode area and the n-type electrode area patterns on the p-type gallium nitride layer and the n-type gallium nitride layer respectively, and then the residual photoresist is cleaned, thereby obtaining the p-type electrode and the n-type electrode; Step 8: Mix hydrofluoric acid and dilute nitric acid in a ratio of 1:10, perform wet silicon etching, and etch the silicon substrate layer into two silicon pillars and a bottom surface for supporting the structure, forming two suspended LED single beam structures. Use HF and HNO3 mixed solution as etching gas, perform etching for 1 minute, and then remove the residual photoresist.

[0033] like Figure 3 and Figure 4 As shown, the light intensity is mainly concentrated on the concave surface of the crescent-shaped resonant beam and gathers inward. Therefore, using a long and straight resonant beam as the receiving end can receive the transmitting end as much as possible, improve the detection efficiency, and better and more accurately perceive the magnitude of acceleration.

Claims

1. A resonant InGaN quantum well micro-opto-electro-mechanical integrated accelerometer device, characterized in that: The invention comprises an LED beam light-emitting device and an LED beam detection device; wherein the LED beam detection device comprises a rectangular beam (9) and two circular disks connected thereto, and the LED beam light-emitting device comprises a crescent-shaped beam (10) and two circular disks connected thereto; wherein the length of the rectangular beam (9) is greater than the length of the crescent-shaped beam (10); wherein the left and right ends of the crescent-shaped beam (10) and the rectangular beam (9) are respectively connected to the middle of the circular disks adjacent to the two sides thereof; wherein the circular disk located on the left is a p-type electrode (7), and the circular disk located on the right is an n-type electrode (8).

2. The resonant InGaN quantum well micro-opto-electro-mechanical integrated accelerometer device according to claim 1, characterized in that: The length ratio of the rectangular beam (9) to the crescent-shaped beam (10) is 1.8:

1.

3. A method for preparing a resonant InGaN quantum well micro-opto-electro-mechanical integrated accelerometer device, characterized in that: The device uses a silicon-based nitride wafer as a carrier, and its structure from bottom to top is a silicon substrate layer (1), an aluminum nitride layer (2), a u-type gallium nitride layer (3), an n-type gallium nitride layer (4), an InGaN quantum well layer (5), and a p-type gallium nitride layer (6), a p-type electrode (7) is arranged above the p-type gallium nitride layer (6), and an n-type electrode (8) is arranged above the edge of the n-type gallium nitride layer (4); wherein the structure above the exposed silicon substrate layer (1) is completely etched away, a stepped table is etched at the edge of the n-type gallium nitride layer (4), the lower table of the stepped table is exposed, the n-type electrode (8) is deposited on the lower table, and the n-type gallium nitride layer (4) and the n-type electrode (8) are exposed on the surface in a circular ring shape; The specific steps are as follows: The first step is to spin-coat a layer of photoresist on the surface of the p-type gallium nitride layer (6) of the silicon-based gallium nitride wafer. Then, optical lithography is used to define two pairs of disks on the spin-coated photoresist, and the patterns are formed by connecting a long and thin straight rectangular beam (9) and a crescent-shaped beam (10). Step 2: depositing a layer of metal nickel with a thickness of 300 nm on the upper surface of the pattern defined in the first step by electron beam evaporation technology; then placing the wafer in an acetone solution for ultrasonic treatment; after the treatment, placing the wafer in ultrapure water and anhydrous ethanol in turn for cleaning, and then cleaning it again in ultrapure water; finally, removing the remaining photoresist, thereby obtaining a mask pattern of nickel; Step 3: At the edge of the silicon-based nitride wafer, etching is performed downward to the middle of the n-type gallium nitride layer (4) by ICP etching technology, thereby successfully transferring the pattern defined in the first step to the n-type gallium nitride layer (4) of the silicon-based nitride wafer, and obtaining the desired LED single resonant beam structure, which is a rectangular beam (9) and a crescent-shaped beam (10); Step 4: After completing the third step, use dilute nitric acid to remove the metal nickel deposited on the surface of the wafer, and then immediately put the wafer into ultrapure water for cleaning; Step 5: Spin-coat photoresist on the surface of each single resonant beam structure LED to prevent the beam structure from being etched away during the etching process, thus playing a protective role; Step 6: Deposit a 300nm thick layer of metal nickel on the defined pattern through electron beam evaporation technology; then, wash the epitaxial wafer in acetone solution, anhydrous ethanol, and ultrapure water in turn. Finally, remove the remaining photoresist to obtain a nickel mask pattern; Step 7: using ICP etching technology, etching the pattern obtained in the sixth step from the n-type gallium nitride layer (4) downward to the surface of the silicon substrate layer (1), thereby transferring the pattern to the silicon substrate layer (1), and finally cleaning the remaining photoresist; Step 8: Using electron beam evaporation technology, a positive electrode is evaporated on the p-type electrode (7) region pattern on the p-type gallium nitride layer (6), and a negative electrode is evaporated on the n-type electrode (8) region pattern on the n-type gallium nitride layer (4), and then the residual photoresist is cleaned to obtain a p-type electrode (7) and an n-type electrode (8), both of which are in the shape of a disk; Step 9: Mix hydrofluoric acid and dilute nitric acid in a ratio of 1:10, and perform wet silicon etching to carve the silicon substrate layer into two silicon pillars and a bottom surface for supporting the structure, forming two suspended LED single beam structures.

4. The method for preparing a resonant InGaN quantum well micro-opto-mechanical-mechanical integrated accelerometer device according to claim 3, characterized in that: The p-type electrode (7) and the n-type electrode (8) are both formed by Au / Ni vapor deposition.

5. The method for preparing a resonant InGaN quantum well micro-opto-electro-mechanical integrated accelerometer device according to claim 3, characterized in that: The p-type electrode (7) is deposited on the upper surface of the p-type gallium nitride layer (6).

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