Gallium nitride-based eight-beam structure inertial navigation system and preparation method thereof

Abstract

The application discloses a gallium nitride-based eight-beam structure inertial navigation system and a preparation method thereof. The inertial navigation system takes a silicon-based nitride as a carrier and comprises, from bottom to top, a silicon substrate layer, an aluminum nitride layer, an n-type gallium nitride layer, a quantum hydrazine layer, a p-type gallium nitride layer, a p-type electrode arranged on the p-type gallium nitride layer, and an n-type electrode arranged at the edge of the n-type gallium nitride layer. The silicon substrate layer is suspended to form a trapezoidal base with a narrow top and a wide bottom below the aluminum nitride layer. The whole inertial navigation system is connected at the head and the tail by four p-type electrodes and four n-type electrodes to form a regular octagon, and the angular velocity and linear velocity of eight directions, i.e. east, west, south, north, northeast, southeast, northwest and southwest, are measured respectively.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of inertial navigation, and in particular to a gallium nitride-based eight-beam structure inertial navigation system and a preparation method thereof. BACKGROUND

[0002] The inertial navigation system is also called an inertial reference system, is a self-contained navigation system which does not rely on external information and does not radiate energy to the outside. The working environment of the inertial navigation system includes not only the air, the ground, but also the water. The basic working principle of the inertial navigation is based on Newton's law of motion, the acceleration of a carrier in an inertial reference system is measured, the acceleration is integrated with respect to time, and the acceleration is transformed into a navigation coordinate system, so that the velocity, the yaw angle and the position in the navigation coordinate system can be obtained.

[0003] The inertial navigation system belongs to a reckoning navigation mode, that is, the position of a next point is reckoned according to the continuously measured heading angle and the velocity of a moving body from a known position, so that the current position of the moving body can be continuously measured. The gyroscope in the inertial navigation system is used to form a navigation coordinate system, so that the measurement axis of the accelerometer is stabilized in the coordinate system, and the heading and the attitude angle are given; the accelerometer is used to measure the acceleration of the moving body, the velocity is obtained by integrating the acceleration with respect to time, and the displacement is obtained by integrating the velocity with respect to time.

[0004] The inertial navigation system in the prior art has the problem of being unable to measure the acceleration and the angular velocity in all directions. SUMMARY

[0005] The application aims at overcoming the defects in the prior art, and provides a gallium nitride-based eight-beam structure inertial navigation system and a preparation method thereof, which can measure the angular velocity and the linear velocity in eight directions of east, west, north and south, northeast, southeast, northwest and southwest.

[0006] In order to solve the problem in the prior art, the application discloses a gallium nitride-based eight-beam structure inertial navigation system, which is characterized by comprising eight beams connected end to end, the eight beams form an octagon, and electrodes are arranged at the connecting positions between the eight beams; each beam is used for measuring the angular velocity and the linear velocity in the direction of the beam.

[0007] Each beam comprises a silicon substrate layer, an aluminum nitride layer, an n-type gallium nitride layer, a quantum well layer and a p-type gallium nitride layer; the silicon substrate layer comprises a bottom surface and a silicon column arranged on the bottom surface, the silicon column supports the aluminum nitride layer, the upper surface of the aluminum nitride layer is connected with the n-type gallium nitride layer, the edge of the n-type gallium nitride layer is in a stepped terrace shape, the quantum well layer is arranged on the upper terrace of the stepped terrace, the p-type gallium nitride layer is arranged on the upper surface of the quantum well layer, and electrodes are arranged on the upper surface of the p-type gallium nitride layer and the lower terrace of the stepped terrace.

[0008] Further, the electrode includes a p-type electrode and an n-type electrode, the p-type electrode is arranged on the upper surface of the p-type gallium nitride layer, and the n-type electrode is arranged on the lower surface of the stepped terrace.

[0009] Further, the edge of the p-type electrode does not coincide with the edge of the p-type gallium nitride layer.

[0010] Further, the edge of the n-type electrode does not coincide with the edge of the n-type gallium nitride layer.

[0011] Further, the p-type electrode and the n-type electrode are both ring electrodes.

[0012] Correspondingly, a preparation method of a gallium nitride-based eight-beam structure inertial navigation system includes the following steps:

[0013] A silicon-based gallium nitride wafer is used as a carrier, photoresist is spin-coated on the upper surface of the P-type gallium nitride of the silicon-based gallium nitride wafer, and then an optical lithography technology is used to define an octagon surrounded by eight beams on the spin-coated photoresist layer.

[0014] An electron beam evaporation technology is used to evaporate metal nickel on the octagon, and finally the residual photoresist is removed.

[0015] An ICP etching technology is used to etch the nitride layer downward until the upper layer of the silicon substrate, so as to transfer the defined octagon to the silicon substrate layer of the silicon-based nitride wafer, and then dilute nitric acid is used to remove the metal nickel.

[0016] Photoresist is spin-coated on the upper surface of the P-type gallium nitride of the silicon-based gallium nitride wafer, and then an optical lithography technology is used to define an octagon on the spin-coated photoresist layer.

[0017] An electron beam evaporation technology is used to evaporate metal nickel on the pattern, and then the residual photoresist is removed.

[0018] An ICP etching technology is used to etch the nitride layer downward until the middle layer of the n-type gallium nitride, so as to transfer the defined octagon to the n-type gallium nitride layer of the silicon-based nitride wafer, and then dilute nitric acid is used to remove the metal nickel.

[0019] Photoresist is spin-coated on the surface of the n-type gallium nitride and the surface of the p-type gallium nitride, and then an optical lithography technology is used to define a pattern of the n-type and p-type electrode regions on the spin-coated photoresist layer.

[0020] An electron beam evaporation technology is used to evaporate a positive electrode on the upper surface of the p-type region transparent electrode pattern and a negative electrode on the upper surface of the n-type region transparent electrode pattern, so that the p-type gallium nitride layer is plated with the positive electrode and the n-type gallium nitride layer is plated with the negative electrode, and finally the residual photoresist is removed to obtain the p-type region electrode and the n-type region electrode.

[0021] The silicon is etched by using a mixed solution of hydrofluoric acid and dilute nitric acid until a trapezoidal base with narrow upper part and wide lower part is formed on the silicon substrate layer (1), and an inertial navigation system surrounded by eight cantilever beams.

[0022] Further, the positive electrode and the negative electrode are both Au / Ni deposited.

[0023] The present application has the following advantages:

[0024] The present application has the following advantages: under acceleration load, the piezoelectric polarization induced by the deformation of the beam causes the quantum confinement Stark effect of quantum hydrazine, causing the movement of the electrically pumped laser mode, thereby establishing the quantitative relationship between acceleration and spectral shift, so each beam laser can be used as an optical-mechanical-electrical integrated accelerometer. The acceleration in four directions can actually reflect the angular velocity from the side, thereby realizing the optical-mechanical-electrical integrated inertial navigation system based on four beams. The system realizes the on-chip inertial navigation system, can realize high-density optoelectronic integration, and the optical signal test avoids the accumulation of electrical noise. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Side view of the eight-beam structure inertial navigation system based on gallium nitride

[0026] Figure 2 Top view of the eight-beam structure inertial navigation system based on gallium nitride.

[0027] Figure 3 Process flow chart of the eight-beam structure inertial navigation system based on gallium nitride.

[0028] In the figure: silicon substrate layer 1, aluminum nitride layer 2, n-type gallium nitride layer 3, quantum hydrazine layer 4, p-type gallium nitride layer 5, p-type electrode 6, n-type electrode 7. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0030] As Figure 1 , 2As shown, the present application is based on a gallium nitride eight-beam structure inertial navigation system, taking a silicon-based nitride wafer as a carrier, from bottom to top, it is a silicon substrate layer 1, an aluminum nitride layer 2, an n-type gallium nitride layer 3, a quantum hydrazine layer 4, a p-type gallium nitride layer 5, and a p-type electrode 6 arranged on the p-type gallium nitride layer 5 and an n-type electrode 7 arranged on the edge of the n-type gallium nitride layer 3. The silicon substrate layer of the inertial navigation system is suspended by wet etching silicon technology, and a trapezoidal base with a narrow top and a wide bottom is formed below the aluminum nitride layer. The entire inertial navigation system is connected by eight beams to form a regular octagon, and electrodes are arranged at the connection between the eight beams. The inertial navigation system measures the angular velocity and linear velocity of the eight directions of east, west, south, north, northeast, southeast, northwest and southwest. The electrode of the p-type gallium nitride layer is covered on the p-type electrode of the p-type gallium nitride layer, and the diameter of the electrode is 200um. The n-type electrode arranged at the edge of the n-type gallium nitride layer is also 200um in diameter. The thickness of the electrode is 120nm.

[0031] As shown in the figure, the present application is based on a gallium nitride eight-beam structure inertial navigation system, taking a silicon-based nitride wafer as a carrier, from bottom to top, it is a silicon substrate layer 1, an aluminum nitride layer 2, an n-type gallium nitride layer 3, a quantum hydrazine layer 4, a p-type gallium nitride layer 5, and a p-type electrode 6 arranged on the p-type gallium nitride layer 5 and an n-type electrode 7 arranged on the edge of the n-type gallium nitride layer 3. The silicon substrate layer of the inertial navigation system is suspended by wet etching silicon technology, and a trapezoidal base with a narrow top and a wide bottom is formed below the aluminum nitride layer. The entire inertial navigation system is connected by eight beams to form a regular octagon, and electrodes are arranged at the connection between the eight beams. The inertial navigation system measures the angular velocity and linear velocity of the eight directions of east, west, south, north, northeast, southeast, northwest and southwest. The electrode of the p-type gallium nitride layer is covered on the p-type electrode of the p-type gallium nitride layer, and the diameter of the electrode is 200um. The n-type electrode arranged at the edge of the n-type gallium nitride layer is also 200um in diameter. The thickness of the electrode is 120nm. Figure 3 As shown in the figure, the present application is based on a gallium nitride eight-beam structure inertial navigation system, taking a silicon-based nitride wafer as a carrier, from bottom to top, it is a silicon substrate layer 1, an aluminum nitride layer 2, an n-type gallium nitride layer 3, a quantum hydrazine layer 4, a p-type gallium nitride layer 5, and a p-type electrode 6 arranged on the p-type gallium nitride layer 5 and an n-type electrode 7 arranged on the edge of the n-type gallium nitride layer 3. The silicon substrate layer of the inertial navigation system is suspended by wet etching silicon technology, and a trapezoidal base with a narrow top and a wide bottom is formed below the aluminum nitride layer. The entire inertial navigation system is connected by eight beams to form a regular octagon, and electrodes are arranged at the connection between the eight beams. The inertial navigation system measures the angular velocity and linear velocity of the eight directions of east, west, south, north, northeast, southeast, northwest and southwest. The electrode of the p-type gallium nitride layer is covered on the p-type electrode of the p-type gallium nitride layer, and the diameter of the electrode is 200um. The n-type electrode arranged at the edge of the n-type gallium nitride layer is also 200um in diameter. The thickness of the electrode is 120nm.

[0032] The first step: the purchased commercial silicon substrate gallium nitride wafer is ultrasonically cleaned with acetone, anhydrous ethanol and deionized water in sequence, and then dried with nitrogen. A spin coater is used to spin coat photoresist AZ-5214 on the front surface of the wafer (the upper surface of the p-type nitride layer 5) at a speed of 4000 revolutions per minute for 40 seconds (the thickness of the photoresist is 1.5 microns). An optical lithography technology is used to define a pattern for etching the substrate silicon layer from top to bottom on the spin-coated photoresist layer. The model of the photoetching machine is MA6.

[0033] The second step: an electron beam evaporation technology is used to evaporate 700nm of metal nickel on the surface of the p-type gallium nitride layer 5, and then the residual photoresist is removed.

[0034] The third step: ICP etching technology is used to etch the nitride layer downward until the upper part of the substrate silicon layer 1, so as to transfer the pattern defined in the first step to the substrate silicon layer 1 of the silicon-based nitride wafer, and then the wafer is placed in a dilute nitric acid solution to remove the residual metal nickel.

[0035] The fourth step: a spin coater is used to spin coat photoresist AZ-5214 on the front surface of the wafer (the surface of the silicon substrate layer 1) at a speed of 4000 revolutions per minute for 40 seconds (the thickness of the photoresist is 1.5 microns). An electron beam evaporation technology is used to evaporate 700nm of metal nickel on the surface of the p-type gallium nitride layer 5, and then the residual photoresist is removed.

[0036] Fifth step: using ICP etching technology to etch the nitride layer downwards until the middle of the n-type gallium nitride layer 3, so as to transfer the pattern defined in the fourth step to the n-type gallium nitride layer 3 of the silicon-based nitride wafer, and then put the wafer into a dilute nitric acid solution to remove the residual nickel metal;

[0037] Sixth step: continue to use the spin coater to spin the photoresist AZ-5214 on the front surface (the surface of the silicon substrate layer 1) of the wafer at a speed of 4000 revolutions per minute for 40 seconds (the thickness of the photoresist is 1.5 microns), define the pattern area of the n-type electrode 6 and the p-type electrode 6 on the spin-coated photoresist layer, and use ICP etching technology to transfer the defined n-type and p-type electrode pattern areas to the n-type gallium nitride layer 3 and the p-type gallium nitride 5 of the wafer respectively, and finally clean the residual photoresist. The photoetching machine model is MA6.

[0038] Seventh step: using electron beam evaporation technology to evaporate metal (Au / Ni) on the electrode pattern, so that the p-type gallium nitride 5 and the n-type gallium nitride layer 3 are respectively plated with the p-type electrode 6 and the n-type electrode 7, and finally remove the residual photoresist.

[0039] The application utilizes optical lithography, ICP etching process and hydrogen fluoride acid and dilute nitric acid mixed solution wet etching process to prepare the inertial navigation system. The reasonable process steps are designed, including the shape of the etching template, to obtain a smooth sidewall, reduce the bending loss of the microcavity and the scattering loss caused by the rough side surface. Considering that the eight-beam structure inertial navigation system based on gallium nitride is small in size, simple to prepare and easy to obtain high-precision inertial navigation system, the applicant uses advanced micro-nano processing technology to design and prepare the inertial navigation system.

[0040] It is to be understood that the terminology used herein such as first and second, and the like, is only intended to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, in the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application. In the drawings of the present application, the filling patterns are only for distinguishing layers, and do not have any other limitations.

[0041] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.

Claims

1. An eight-beam inertial navigation system based on gallium nitride, characterized in that, It consists of eight beams connected end to end, forming an octagon. Electrodes are placed at the joints between the eight beams, and each beam is used to measure the angular velocity and linear velocity in its direction. Each beam includes a silicon substrate layer (1), an aluminum nitride layer (2), an n-type gallium nitride layer (3), a quantum well layer (4), and a p-type gallium nitride layer (5). The silicon substrate layer (1) includes a bottom surface and a silicon pillar disposed on the bottom surface. The silicon pillar supports the aluminum nitride layer (2). The upper surface of the aluminum nitride layer (2) is connected to the n-type gallium nitride layer (3). The edge of the n-type gallium nitride layer (3) is a stepped platform. The quantum well layer (4) is disposed on the upper platform of the stepped platform. The p-type gallium nitride layer (5) is disposed on the upper surface of the quantum well layer (4). Electrodes are disposed on the upper surface of the p-type gallium nitride layer (5) and the lower platform of the stepped platform. The electrode includes a p-type electrode (6) and an n-type electrode (7). The p-type electrode (6) is disposed on the upper surface of the p-type gallium nitride layer (5), and the n-type electrode (7) is disposed on the lower platform of the stepped platform. Both the p-type electrode (6) and the n-type electrode (7) are ring electrodes.

2. The gallium nitride-based eight-beam inertial navigation system according to claim 1, characterized in that, The edge of the p-type electrode (6) does not coincide with the edge of the p-type gallium nitride layer (5).

3. The gallium nitride-based eight-beam inertial navigation system according to claim 1, characterized in that, The edge of the n-type electrode (7) does not coincide with the edge of the n-type gallium nitride layer (3).

4. The method for fabricating an eight-beam inertial navigation system based on gallium nitride according to claim 1, characterized in that, Includes the following steps: Using a silicon-based gallium nitride wafer as a carrier, photoresist is spin-coated onto the surface of the P-type gallium nitride (5) of the silicon-based gallium nitride wafer, and then an octagon surrounded by eight beams is defined on the spin-coated photoresist layer using optical lithography. Electron beam evaporation technology was used to deposit metallic nickel on the octagon, and finally the residual photoresist was removed. The nitride layer is etched down to the top of the substrate silicon layer (1) using ICP etching technology, thereby transferring the defined octagon to the silicon substrate layer (1) of the silicon-based nitride wafer, and then the metallic nickel is removed with dilute nitric acid. Photoresist was re-spin-coated onto the surface of the P-type gallium nitride (5) on the silicon-based gallium nitride wafer, and then an octagon was defined on the spin-coated photoresist layer using optical lithography. Electron beam evaporation is used to deposit metallic nickel on the pattern, followed by removal of residual photoresist; The nitride layer was etched down to the middle layer of the n-type gallium nitride (3) using ICP etching technology, thereby transferring the defined octagon to the n-type gallium nitride layer (3) of the silicon-based nitride wafer, and then the metallic nickel was removed with dilute nitric acid. Photoresist was spin-coated on the n-type gallium nitride (3) surface and the p-type gallium nitride (5) surface, and then optical lithography was used to define the patterns of the n-type and p-type electrode regions on the spin-coated photoresist layer; A positive electrode is deposited on the upper surface of the transparent electrode pattern in the p-type region using electron beam evaporation technology, and a negative electrode is deposited on the upper surface of the transparent electrode pattern in the n-type region, so that the p-type gallium nitride layer (5) is coated with a positive electrode and the n-type gallium nitride layer (3) is coated with a negative electrode. Finally, the residual photoresist is removed to obtain the p-type electrode (6) and the n-type electrode (6). The silicon substrate was etched by wet etching with a mixture of hydrofluoric acid and dilute nitric acid until a trapezoidal base narrow at the top and wide at the bottom was formed on the silicon substrate (1), and an inertial navigation system surrounded by eight beams was formed.

5. The method for fabricating an eight-beam inertial navigation system based on gallium nitride according to claim 4, characterized in that, Both the positive and negative electrodes are vapor-deposited Au / Ni.

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