Gallium nitride sensor and preparation method thereof and hydrogen detection device

Abstract

The present application proposes a gallium nitride sensor and a preparation method thereof and a hydrogen detection device. The gallium nitride sensor includes: a substrate; a buffer layer, a channel layer, a barrier layer, a cap layer and a source-drain metal layer arranged in sequence on one side of the substrate, wherein the channel layer and the barrier layer form a heterojunction; a passivation layer, wherein the passivation layer covers part of the surface of the channel layer, part of the surface of the metal layer and at least part of the surface of the cap layer; an electrode, wherein the electrode is arranged on the side of the source-drain metal layer away from the substrate, and the electrode covers at least part of the surface of the source-drain metal layer and part of the surface of the channel layer; a plurality of through holes, wherein the through holes penetrate the passivation layer, the cap layer, the barrier layer, the channel layer and the buffer layer, and are arranged at intervals between two adjacent through holes, a cantilever is formed between the through holes, and the cantilever is arranged at intervals from the surface of the substrate close to the buffer layer. Thus, hydrogen can be specifically identified and the content of hydrogen can be detected.

Description

Technical Field

[0001] The present application relates to the field of precision detection and micro-nano processing, and specifically, to a gallium nitride sensor and a preparation method thereof, and a hydrogen detection device. Background Art

[0002] Hydrogen has the advantages of high combustion calorific value (142kJ / g), low minimum ignition energy (0.017mJ), wide flammable range (4-75%), and fast combustion speed. It is one of the best clean energy carriers. The combustion product of hydrogen is water, which is pollution-free and can be converted into hydrogen and oxygen again. It is used in fuel cells and nuclear fusion. It is one of the most promising candidates for future transportation and energy supply. Hydrogen is tasteless, colorless, and odorless. Therefore, in the production, storage, and use of hydrogen, in order to avoid the dangers of explosion, fire, etc. caused by hydrogen, it is necessary to quickly and accurately detect the content of hydrogen. Gas sensors such as electrochemical sensors and catalytic sensors are widely used to monitor hydrogen concentration. Although such sensors show high sensitivity when detecting percentage concentrations of hydrogen, they have many disadvantages when continuously monitoring hydrogen concentration. For example, the service life of chemical sensors is short; the catalytic materials of catalytic sensors are easily poisoned by compounds containing elements such as P, S, Si, as well as CO and hydrocarbons, thereby reducing their sensitivity. Therefore, the current sensors need to be further improved. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] In one aspect of the present invention, a gallium nitride sensor is provided, comprising: a substrate; a buffer layer, a channel layer, a barrier layer, a cap layer and a source-drain metal layer arranged in sequence on one side of the substrate, the channel layer and the barrier layer forming a heterojunction; a passivation layer, the passivation layer covering a portion of the surface of the channel layer, a portion of the surface of the metal layer and at least a portion of the surface of the cap layer; an electrode, the electrode being arranged on a side of the source-drain metal layer away from the substrate, the electrode covering at least a portion of the surface of the source-drain metal layer and a portion of the surface of the channel layer; a plurality of through holes, the through holes penetrating the passivation layer, the cap layer, the barrier layer, the channel layer and the buffer layer, two adjacent through holes being arranged at intervals, a cantilever being formed between the through holes, and the cantilever being arranged at intervals from a surface of the substrate close to the buffer layer.

[0005] The gallium nitride sensor involved in the present application utilizes the piezoelectric polarization and self-polarization effects of the heterostructure formed by the barrier layer and the channel layer to induce a two-dimensional electron gas (2DEG) at the interface of the channel layer. After applying voltage to the source-drain metal layer, the highly conductive 2DEG is used as a heater through Joule heating to heat the cantilever in situ. When a gas with a high thermal conductivity flows through the cantilever, the gas takes away part of the heat to reduce the temperature of the 2DEG, increase the channel mobility of the gallium nitride sensor, and enhance the piezoelectric effect, thereby increasing the source-drain current. By detecting the change in the cantilever current, specific detection and content detection of high thermal conductivity gas can be achieved. The cantilever is set in the air to prevent heat from being dissipated from the substrate and reduce the power consumption of the device.

[0006] According to some embodiments of the present application, the electrode includes a first heating electrode and a first detection electrode, and the first heating electrode and the first detection electrode are arranged at both ends of the gallium nitride sensor along a first direction; the cantilever includes a first section and a second section, one end of the first section is connected to the first heating electrode, one end of the second section is connected to the first detection electrode, and the other end of the first section is connected to the other end of the second section.

[0007] According to some embodiments of the present application, the electrode also includes a second heating electrode and a second detection electrode, the first heating electrode and the second heating electrode are arranged at both ends of the gallium nitride sensor along the second direction, the first detection electrode and the second detection electrode are arranged at both ends of the gallium nitride sensor along the second direction, and the first direction and the second direction intersect; the cantilever also includes a third segment and a fourth segment, one end of the third segment is connected to the second heating electrode, one end of the fourth segment is connected to the second detection electrode, and the other end of the third segment is connected to the other end of the fourth segment.

[0008] According to some embodiments of the present application, the thickness of the substrate is 100 μm-1000 μm.

[0009] According to some embodiments of the present application, the buffer layer has a thickness of 1.4 μm-5 μm.

[0010] According to some embodiments of the present application, the thickness of the channel layer is 0.1 μm-0.5 μm.

[0011] According to some embodiments of the present application, the barrier layer has a thickness of 10 nm-50 nm.

[0012] According to some embodiments of the present application, the thickness of the cap layer is 1nm-5nm.

[0013] According to some embodiments of the present application, the thickness of the passivation layer is 50nm-600nm.

[0014] According to some embodiments of the present application, materials forming the buffer layer, the channel layer, and the cap layer independently include GaN.

[0015] According to some embodiments of the present application, the material forming the source-drain metal layer includes at least one of Ti, Al, W, Cr, Ni, Pt or Au.

[0016] According to some embodiments of the present application, the material forming the passivation layer includes at least one of SiO2, Si3N4 or Al2O3.

[0017] In another aspect of the present application, a method for preparing the gallium nitride sensor proposed in the first aspect of the present application is proposed, comprising: providing a substrate; sequentially forming a buffer layer, a channel layer, a barrier layer, a cap layer, a source-drain metal layer and a passivation layer on one side of the substrate, wherein the channel layer and the barrier layer constitute a heterojunction, and the passivation layer covers a portion of the surface of the channel layer, a portion of the surface of the metal layer and at least a portion of the surface of the cap layer; forming an electrode, wherein the electrode is arranged on a side of the source-drain metal layer away from the substrate, and the electrode covers at least a portion of the surface of the source-drain metal layer and a portion of the surface of the channel layer; forming a plurality of through holes, wherein the through holes penetrate the passivation layer, the cap layer, the barrier layer, the channel layer and the buffer layer, and two adjacent through holes are arranged at intervals, and a cantilever is formed between the through holes, and the cantilever is arranged at intervals from the surface of the substrate near the buffer layer. Thus, the method has a simple process, is easy to integrate and expand, is convenient for large-scale circuit connection and high-throughput gas detection, and the prepared gallium nitride sensor can realize specific detection and content detection of high thermal conductivity gas.

[0018] According to some embodiments of the present application, the method includes: forming a whole layer of original buffer layer, a whole layer of original channel layer, a whole layer of original barrier layer and a whole layer of original cap layer in sequence on one side of the original substrate; etching the original cap layer, the original barrier layer and part of the original channel layer for the first time to form a patterned cap layer, a patterned barrier layer and a patterned channel layer; forming a whole layer of original source and drain metal layer on the side of the patterned channel layer away from the substrate, the original source and drain metal layer covering the patterned cap layer and the exposed patterned channel layer, etching the original source and drain metal layer for the first time The layer is stripped for the first time to form the source and drain metal layer; the original buffer layer, the patterned channel layer, the patterned barrier layer and the patterned cap layer are etched for the second time to form a plurality of through holes; a whole original passivation layer is formed on the side of the channel layer away from the substrate, and the original passivation layer is etched for the third time to form the passivation layer; a whole original electrode layer is formed on the side of the passivation layer away from the substrate, and the original electrode layer is stripped for the second time to form the electrode layer; the original substrate is etched for the fourth time through the through holes.

[0019] According to some embodiments of the present application, the second stripping further includes: forming a first heating electrode and a first detection electrode, the first heating electrode and the first detection electrode are arranged at both ends of the gallium nitride sensor along the first direction, the second etching further includes: forming a first segment and a second segment of the cantilever, one end of the first segment is connected to one end of the second segment, the other end of the first segment is connected to the first heating electrode, and the other end of the second segment is connected to the first detection electrode; and / or the second stripping further includes: forming a second heating electrode and a second detection electrode, the first heating electrode and the second heating electrode are arranged at both ends of the gallium nitride sensor along the second direction, the first detection electrode and the second detection electrode are arranged at both ends of the gallium nitride sensor along the second direction, and the first direction and the second direction intersect; the second etching further includes: forming a third segment and a fourth segment of the cantilever, one end of the third segment is connected to one end of the fourth segment, the other end of the third segment is connected to the second heating electrode, and the other end of the fourth segment is connected to the second detection electrode.

[0020] According to some embodiments of the present application, the first etching, the second etching and the third etching are performed using an inductively coupled plasma etching process.

[0021] According to some embodiments of the present application, the fourth etching is performed by isotropic etching.

[0022] In yet another aspect of the present application, a hydrogen detection device is provided, comprising the gallium nitride sensor provided in the first aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1 A schematic structural diagram of a gallium nitride sensor according to an embodiment of the present application is shown.

[0025] Figure 2 Shows Figure 1 Schematic diagram of hydrogen detection using gallium nitride sensor.

[0026] Figure 3 Shows Figure 1 A top view of the GaN sensor in Figure 1.

[0027] Figure 4 A schematic diagram showing the process of preparing a gallium nitride sensor according to an embodiment of the present application.

[0028] Figure 5 Shows Figure 1 Schematic diagram of the hydrogen detection process of the gallium nitride sensor.

[0029] Reference numerals:

[0030] 1: GaN sensor; 11: substrate; 11”: original substrate; 12: buffer layer; 12”: original buffer layer; 13: channel layer; 13”: original channel layer; 13’: patterned channel layer; 14: barrier layer; 14”: original barrier layer; 14’: patterned barrier layer; 15: cap layer; 15”: original cap layer; 15’: patterned cap layer; 16: source-drain metal layer; 16”: original source-drain metal layer; 17: passivation layer; 17″: original passivation layer; 18: electrode; 19: through hole; 20: cantilever; 181: first heating electrode; 182: first detection electrode; 183: second heating electrode; 184: second detection electrode; 201: first segment; 202: second segment; 203: third segment; 204: fourth segment; 205: fifth segment; 206: sixth segment; 207: seventh segment; 208: eighth segment. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0032] In one aspect of the present application, a gallium nitride sensor 1 is provided, referring to Figure 1 and Figure 2 The gallium nitride sensor 1 includes: a substrate 11; a buffer layer 12, a channel layer 13, a barrier layer 14, a cap layer 15 and a source-drain metal layer 16 arranged on one side of the substrate 11 in sequence, wherein the channel layer 13 and the barrier layer 14 form a heterojunction; a passivation layer 17, wherein the passivation layer 17 covers a portion of the surface of the channel layer 13, a portion of the surface of the metal layer and at least a portion of the surface of the cap layer 15; an electrode 18, wherein the electrode 18 is arranged on a side of the source-drain metal layer 16 away from the substrate 11, wherein the electrode 18 covers at least a portion of the surface of the source-drain metal layer 16 and a portion of the surface of the channel layer 13; and a plurality of through holes 19, wherein the through holes 19 penetrate the passivation layer 17, the cap layer 15, the barrier layer 14, the channel layer 13 and the buffer layer 12, and are arranged at intervals between two adjacent through holes 19, and a cantilever 20 is formed between the through holes 19, and the cantilever 20 is arranged at intervals from a surface of the substrate 11 close to the buffer layer 12.

[0033] The gallium nitride sensor 1 involved in the present application utilizes the piezoelectric polarization and self-polarization effects of the heterostructure formed by the barrier layer 14 and the channel layer 13 to induce a two-dimensional electron gas (2DEG) at the interface of the channel layer 13. During the gas detection process, a voltage is applied to the source-drain metal layer 16, and the highly conductive 2DEG is used as a heater through Joule heating to heat the cantilever 20 in situ. When a gas with a high thermal conductivity flows through the cantilever 20, the gas takes away part of the heat to reduce the temperature of the 2DEG, increase the channel mobility of the gallium nitride sensor 1, and enhance the piezoelectric effect, thereby increasing the source-drain current. By detecting the change in the current of the cantilever 20, specific detection and content detection of high thermal conductivity gas can be achieved. The cantilever 20 of the gallium nitride sensor 1 proposed in the present application is suspended, which can prevent heat from being dissipated from the substrate 11 and reduce the power consumption of the device.

[0034] According to some embodiments of the present application, reference Figure 3 , the electrode 18 may include a first heating electrode 181 and a first detection electrode 182, the first heating electrode 181 and the first detection electrode 182 are arranged at two ends of the gallium nitride sensor 1 along the first direction; the cantilever 20 includes a first section 201 and a second section 202, one end of the first section 201 is connected to the first heating electrode 181, one end of the second section 202 is connected to the first detection electrode 182, and the other end of the first section 201 is connected to the other end of the second section 202. Specifically, during the gas detection process, voltages are applied to the first heating electrode 181 and the first detection electrode 182 respectively to heat the first section 201 and the second section 202 of the cantilever 20. When the temperature of the cantilever 20 is stable, the gas to be tested is passed above the gallium nitride sensor 1. The gas to be tested flowing through the through hole 19 can quickly take away the heat to reduce the temperature of the cantilever 20, thereby increasing the channel mobility and piezoelectric effect of the device, increasing the detection current, and realizing the specific detection and content detection of high thermal conductivity gas through the change of current.

[0035] According to some embodiments of the present application, reference Figure 3 A fifth section 205 and a sixth section 206 may be included between the first section 201 and the second section 202, one end of the first section 201 is connected to the first heating electrode 181, one end of the second section 202 is connected to the first detection electrode 182, one end of the fifth section 205 is connected to the other end of the first section 201, the other end of the fifth section 205 is connected to one end of the sixth section 206, and the other end of the sixth section 206 is connected to the other end of the second section 202. Thus, the area of ​​the cantilever 20 is increased, and the mechanical robustness of the cantilever is improved.

[0036] According to some embodiments of the present application, the flow rate of the gas to be tested can be 0.001m 3 / h~1m 3 / h.

[0037] According to some embodiments of the present application, the high thermal conductivity gas includes hydrogen.

[0038] According to some embodiments of the present application, reference Figure 3 , the electrode 18 may also include a second heating electrode 183 and a second detection electrode 184, the first heating electrode 181 and the second heating electrode 183 are arranged at the two ends of the gallium nitride sensor 1 along the second direction, the first detection electrode 182 and the second detection electrode 184 are arranged at the two ends of the gallium nitride sensor 1 along the second direction, and the first direction and the second direction intersect; the cantilever 20 may also include a third section 203 and a fourth section 204, one end of the third section 203 is connected to the second heating electrode 183, one end of the fourth section 204 is connected to the second detection electrode 184, and the other end of the third section 203 is connected to the other end of the fourth section 204. Specifically, during the gas detection process, voltages are applied to the first heating electrode 181, the second heating electrode 183, the first detection electrode 182, and the second detection electrode 184 to heat the first section 201, the second section 202, the third section 203, and the fourth section 204 of the cantilever 20. When the temperature of the cantilever 20 is stable, the gas to be tested is passed over the gallium nitride sensor 1. The gas to be tested flowing through the through hole 19 can quickly take away the heat to reduce the temperature of the cantilever 20, thereby increasing the channel mobility and piezoelectric effect of the device, increasing the detection current, and realizing the specific detection and content detection of high thermal conductivity gas through the change of current. In this way, the heating efficiency is improved and the detection accuracy is improved.

[0039] According to some embodiments of the present application, reference Figure 3 The cantilever 20 may further include a seventh section 207 and an eighth section 208, one end of the third section 203 is connected to the second heating electrode 183, one end of the fourth section 204 is connected to the second detection electrode 184, one end of the seventh section 207 is connected to the other end of the third section 203, the other end of the seventh section 207 is connected to one end of the eighth section 208, and the other end of the eighth section 208 is connected to the other end of the fourth section 204. Thus, the area of ​​the cantilever 20 is increased, and after the cantilever 20 is heated, the uniformity of the temperature distribution of the cantilever 20 is improved, and the mechanical robustness of the cantilever 20 is increased.

[0040] According to some embodiments of the present application, the thickness of the substrate 11 may be 100 μm-1000 μm, for example, 100 μm, 300 μm, 500 μm, 700 μm, 900 μm or 1000 μm, etc., or may be a range consisting of any of the above values.

[0041] According to some embodiments of the present application, the thickness of the buffer layer 12 may be 1.4 μm-5 μm, for example, 1.4 μm, 2 μm, 3 μm, 4 μm or 5 μm, etc., or may be a range consisting of any of the above values.

[0042] According to some embodiments of the present application, the thickness of the channel layer 13 may be 0.1 μm-0.5 μm, for example, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm or 0.5 μm, etc., or may be within a range consisting of any of the above values.

[0043] According to some embodiments of the present application, the thickness of the barrier layer 14 may be 10 nm-50 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm or 50 nm, or may be a range consisting of any of the above values.

[0044] According to some embodiments of the present application, the thickness of the cap layer 15 may be 1 nm-5 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm or 5 nm, or may be within a range consisting of any of the above values.

[0045] According to some embodiments of the present application, the thickness of the passivation layer 17 may be 50nm-600nm, for example, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm or 600nm, or may be a range consisting of any of the above values.

[0046] According to some embodiments of the present application, the materials forming the buffer layer 12, the channel layer 13 and the cap layer 15 include GaN respectively and independently. According to some embodiments of the present application, the material forming the barrier layer 14 may include AlGaN. Thus, the AlGaN / GaN heterostructure can generate a 2DEG with high electron mobility at the interface of the channel layer 13.

[0047] According to some embodiments of the present application, the material forming the source-drain metal layer 16 includes at least one of Ti, Al, W, Cr, Ni, Pt or Au.

[0048] According to some embodiments of the present application, the material forming the passivation layer 17 includes at least one of SiO 2 , Si 3 N 4 or Al 2 O 3 .

[0049] In another aspect of the present application, a method for preparing the aforementioned gallium nitride sensor 1 is proposed, referring to Figure 4 , the method comprising:

[0050] S100: Providing an original substrate 11"

[0051] According to some embodiments of the present application, the material of the original substrate 11 ″ may be silicon.

[0052] According to some embodiments of the present application, the silicon substrate 11 includes a P-type silicon substrate 11 or an N-type silicon substrate 11 .

[0053] S200: On one side of the original substrate 11", a whole layer of original buffer layer 12", a whole layer of original channel layer 13", a whole layer of original barrier layer 14" and a whole layer of original cap layer 15" are sequentially formed.

[0054] According to some embodiments of the present application, a whole layer of original buffer layer 12", a whole layer of original channel layer 13", a whole layer of original barrier layer 14" and a whole layer of original cap layer 15" are sequentially formed on one side of the original substrate 11", and the original cap layer 15", the original barrier layer 14" and part of the original channel layer 13" are etched for the first time to form a patterned cap layer 15', a patterned barrier layer 14' and a patterned channel layer 13', and electrical isolation is made by the first etching.

[0055] According to some embodiments of the present application, the first etching may adopt an inductively coupled plasma etching process.

[0056] S300: Forming a whole layer of original source and drain metal layer 16 on the side of the patterned channel layer 13' away from the substrate 11"

[0057] According to some embodiments of the present application, a whole layer of original source-drain metal layer 16'' is formed on the side of the patterned channel layer 13' facing away from the substrate 11, the original source-drain metal layer 16'' covers the patterned cap layer 15' and the exposed patterned channel layer 13', and the original source-drain metal layer 16'' is stripped for the first time to form the source-drain metal layer 16.

[0058] S400: performing a second etching on the original buffer layer 12 ″, the patterned channel layer 13 ′, the patterned barrier layer 14 ′ and the patterned cap layer 15 ′

[0059] According to some embodiments of the present application, the original buffer layer 12 ″, the patterned channel layer 13 ′, the patterned barrier layer 14 ′ and the patterned cap layer 15 ′ are etched a second time to form the plurality of through holes 19 .

[0060] According to some embodiments of the present application, the second etching may adopt an inductively coupled plasma etching process.

[0061] According to some embodiments of the present application, the second etching may also include: forming a first section 201 and a second section 202 of the cantilever 20, one end of the first section 201 is connected to one end of the second section 202, the other end of the first section 201 is connected to the first heating electrode 181, and the other end of the second section 202 is connected to the first detection electrode 182.

[0062] According to some embodiments of the present application, the second etching may also include: forming a third segment 203 and a fourth segment 204 of the cantilever 20, one end of the third segment 203 is connected to one end of the fourth segment 204, the other end of the third segment 203 is connected to the second heating electrode 183, and the other end of the fourth segment 204 is connected to the second detection electrode 184.

[0063] S500: forming a whole layer of original passivation layer 17 on the side of the channel layer 13 away from the substrate 11"

[0064] According to some embodiments of the present application, a whole original passivation layer 17 ″ is formed on a side of the channel layer 13 facing away from the substrate 11 , and the original passivation layer 17 ″ is etched for a third time to form the passivation layer 17 .

[0065] According to some embodiments of the present application, the third etching may be performed using an inductively coupled plasma etching process.

[0066] S600: Forming a whole original electrode layer on the side of the passivation layer 17 away from the substrate 11 (not shown in the figure)

[0067] According to some embodiments of the present application, a whole original electrode layer is formed on the side of the passivation layer 17 facing away from the substrate 11 , and the original electrode layer is peeled off for a second time to form the electrode 18 .

[0068] According to some embodiments of the present application, the second stripping may include: forming a first heating electrode 181 and a first detection electrode 182 , wherein the first heating electrode 181 and the first detection electrode 182 are disposed at two ends of the gallium nitride sensor 1 along the first direction.

[0069] According to some embodiments of the present application, the second stripping may also include: forming a second heating electrode 183 and a second detection electrode 184, the first heating electrode 181 and the second heating electrode 183 are arranged at both ends of the gallium nitride sensor 1 along the second direction, the first detection electrode 182 and the second detection electrode 184 are arranged at both ends of the gallium nitride sensor 1 along the second direction, and the first direction and the second direction intersect.

[0070] S700: Performing a fourth etching on the original substrate 11″

[0071] According to some embodiments of the present application, the original substrate 11 ″ is etched for the fourth time through the through hole 19 .

[0072] According to some embodiments of the present application, the fourth etching may be performed by isotropic etching.

[0073] According to some embodiments of the present application, the etching gas flow rate during the isotropic etching process can be 200sccm-300sccm, for example, it can be 200sccm, 220sccm, 240sccm, 260sccm, 280sccm or 300sccm, etc., or it can be a range composed of any of the above values.

[0074] According to some embodiments of the present application, the etching pressure during the isotropic etching process can be 1mBar-4mBar, for example, it can be 1mBar, 1.5mBar, 2mBar, 2.5mBar, 3mBar, 3.5mBar or 4mBar, etc., or it can be a range composed of any of the above values.

[0075] In a second aspect of the present application, a hydrogen detection device is provided, comprising the aforementioned gallium nitride sensor 1. The hydrogen detection device provided in the present application can specifically identify hydrogen and detect the hydrogen content.

[0076] Example 1

[0077] (1) Provide a 6-inch single-sided polished Si substrate with a thickness of 500 μm and an N-type doping type;

[0078] (2) forming a 1.4 μm GaN buffer layer, a 500 nm GaN channel layer, a 25 nm AlGaN barrier layer, and a 2 nm GaN cap layer in sequence on the polished surface of the Si substrate;

[0079] (3) Locally etch the GaN material to make electrical isolation, deposit the metal layer (Ti / Al / Ti / Au) and pattern it, and perform high-temperature nitrogen annealing to form ohmic contact;

[0080] (4) Locally etch GaN onto the Si substrate and pattern it to determine the cantilever shape;

[0081] (5) depositing a 300 nm SiO2 passivation layer, and locally etching and patterning the windows required to expose the heating electrode and the detection electrode;

[0082] (6) depositing metal Ti / Au and patterning to prepare heating electrodes and detection electrodes;

[0083] (7) Use XeF2 isotropic etching to make the cantilever, with an etching gas flow rate of 240 sccm and an etching pressure of 2.5 mBar.

[0084] refer to Figure 5 , voltages were applied to the heating electrode and the detection electrode, respectively, with an input power of 65 mW, the cantilever was heated and stabilized at 200 °C, the voltage applied to the detection electrode was 15 V, and the hydrogen flow rate was 0.1 m 3 / h, hydrogen with high thermal conductivity can quickly take away heat and reduce the cantilever temperature, which greatly increases the channel mobility of the device and significantly enhances the piezoelectric effect, resulting in a rapid increase in the detection current, realizing the specific detection of hydrogen and hydrogen concentration detection.

[0085] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0086] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0087] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0088] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0090] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A gallium nitride sensor, characterized in that: include: substrate; A buffer layer, a channel layer, a barrier layer, a cap layer and a source-drain metal layer are sequentially arranged on one side of the substrate, wherein the channel layer and the barrier layer form a heterojunction; a passivation layer, the passivation layer covering a portion of the surface of the channel layer, a portion of the surface of the source / drain metal layer, and at least a portion of the surface of the cap layer; An electrode, wherein the electrode is disposed on a side of the source-drain metal layer away from the substrate, and the electrode covers at least a portion of a surface of the source-drain metal layer and a portion of a surface of the channel layer; A plurality of through holes, wherein the through holes penetrate the passivation layer, the cap layer, the barrier layer, the channel layer and the buffer layer, two adjacent through holes are arranged at intervals, a cantilever is formed between the through holes, and the cantilever is arranged at intervals from a surface of the substrate close to the buffer layer, The electrodes include a first heating electrode and a first detection electrode, and the first heating electrode and the first detection electrode are arranged at two ends of the gallium nitride sensor along a first direction; The cantilever comprises a first section and a second section, one end of the first section is connected to the first heating electrode, one end of the second section is connected to the first detection electrode, and the other end of the first section is connected to the other end of the second section. The electrode also includes a second heating electrode and a second detection electrode. The first heating electrode and the second heating electrode are arranged at two ends of the gallium nitride sensor along a second direction. The first detection electrode and the second detection electrode are arranged at two ends of the gallium nitride sensor along the second direction. The first direction and the second direction intersect.

2. The gallium nitride sensor according to claim 1, characterized in that: The cantilever further includes a third section and a fourth section, one end of the third section is connected to the second heating electrode, one end of the fourth section is connected to the second detection electrode, and the other end of the third section is connected to the other end of the fourth section.

3. The gallium nitride sensor according to claim 1, characterized in that: Satisfy at least one of the following conditions: The thickness of the substrate is 100 μm-1000 μm; The thickness of the buffer layer is 1.4 μm-5 μm; The thickness of the channel layer is 0.1µm-0.5µm; The thickness of the barrier layer is 10nm-50nm; The thickness of the cap layer is 1nm-5nm; The thickness of the passivation layer is 50nm-600nm.

4. The gallium nitride sensor according to any one of claims 1 to 3, characterized in that: Satisfy at least one of the following conditions: The materials forming the buffer layer, the channel layer and the cap layer independently include GaN; The material forming the source-drain metal layer includes at least one of Ti, Al, W, Cr, Ni, Pt or Au; The material forming the passivation layer includes at least one of SiO2, Si3N4 or Al2O3.

5. A method for preparing the gallium nitride sensor according to any one of claims 1 to 4, characterized in that: include: providing a substrate; A buffer layer, a channel layer, a barrier layer, a cap layer, a source-drain metal layer and a passivation layer are sequentially formed on one side of the substrate, wherein the channel layer and the barrier layer form a heterojunction, and the passivation layer covers a portion of the surface of the channel layer, a portion of the surface of the source-drain metal layer and at least a portion of the surface of the cap layer; forming an electrode, wherein the electrode is disposed on a side of the source / drain metal layer away from the substrate, and the electrode covers at least a portion of the surface of the source / drain metal layer and a portion of the surface of the channel layer; A plurality of through holes are formed, the through holes penetrating the passivation layer, the cap layer, the barrier layer, the channel layer and the buffer layer, two adjacent through holes are spaced apart, a cantilever is formed between the through holes, and the cantilever is spaced apart from the surface of the substrate close to the buffer layer.

6. The method according to claim 5, characterized in that The method comprises: Sequentially forming a whole layer of original buffer layer, a whole layer of original channel layer, a whole layer of original barrier layer and a whole layer of original cap layer on one side of the original substrate, and performing a first etching on the original cap layer, the original barrier layer and a part of the original channel layer to form a patterned cap layer, a patterned barrier layer and a patterned channel layer; forming a whole layer of original source-drain metal layer on a side of the patterned channel layer away from the substrate, the original source-drain metal layer covering the patterned cap layer and the exposed patterned channel layer, and performing a first stripping operation on the original source-drain metal layer to form the source-drain metal layer; Performing a second etching on the original buffer layer, the patterned channel layer, the patterned barrier layer and the patterned cap layer to form a plurality of the through holes; forming a whole original passivation layer on a side of the channel layer away from the substrate, and performing a third etching on the original passivation layer to form the passivation layer; forming a whole original electrode layer on the side of the passivation layer away from the substrate, and performing a second peeling on the original electrode layer to form the electrode layer; The original substrate is etched for the fourth time through the through hole.

7. The method according to claim 6, characterized in that The second stripping further includes: forming a first heating electrode and a first detection electrode, wherein the first heating electrode and the first detection electrode are arranged at two ends of the gallium nitride sensor along the first direction, and the second etching further includes: forming a first section and a second section of the cantilever, wherein one end of the first section is connected to one end of the second section, the other end of the first section is connected to the first heating electrode, and the other end of the second section is connected to the first detection electrode; and The second stripping further includes: forming a second heating electrode and a second detection electrode, the first heating electrode and the second heating electrode are arranged at both ends of the gallium nitride sensor along the second direction, the first detection electrode and the second detection electrode are arranged at both ends of the gallium nitride sensor along the second direction, and the first direction and the second direction intersect; the second etching further includes: forming a third segment and a fourth segment of the cantilever, one end of the third segment is connected to one end of the fourth segment, the other end of the third segment is connected to the second heating electrode, and the other end of the fourth segment is connected to the second detection electrode.

8. The method according to claim 6 or 7, characterized in that: Satisfy at least one of the following conditions: The first etching, the second etching and the third etching are performed by using an inductively coupled plasma etching process; The fourth etching adopts isotropic etching.

9. A hydrogen detection device, characterized in that: A gallium nitride sensor comprising any one of claims 1 to 4.

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