CN107621317A - A surface acoustic wave high temperature pressure sensor chip based on SOI and piezoelectric film and its preparation method - Google Patents

Abstract

The present invention proposes a kind of surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane and preparation method thereof, the surface acoustic wave chip of high-temp pressure sensor includes soi chip substrate, formed with pressure sensitive layer in soi chip substrate, formed with piezoelectric membrane on pressure sensitive layer, formed with interdigital transducer and reflecting grating on piezoelectric membrane；The chamber of reference pressure is provided when extending to pressure sensitive layer formed with detection pressure from soi chip substrate bottom surface in soi chip substrate.The surface acoustic wave chip of high-temp pressure sensor small volume of the present invention, wireless receiving and dispatching can be realized by being operated in radio band, and metering system is flexible, thus has very big application potential in high temperature pressure measurement field.

Description

A surface acoustic wave high temperature pressure sensor chip based on SOI and piezoelectric film and its its preparation method

technical field

The invention belongs to the technical field of semiconductor design and manufacture, relates to MEMS sensors, in particular to a surface acoustic wave high-temperature pressure sensor chip based on SOI and a piezoelectric film and a preparation method thereof.

Background technique

Pressure measurement in high temperature environment is one of the key points and difficulties of measurement and control technology. In the fields of aerospace, national defense, petrochemical, and automobile industries, it is often necessary to measure and control pressure in a high-temperature environment. High-performance high-temperature pressure sensors are one of the key components in the above-mentioned fields.

The silicon piezoresistive pressure sensor widely used at present uses a P-N junction to isolate the strain bridge and the strain film. Its technology is mature and its performance is excellent. , the performance of the sensor will seriously deteriorate or even fail. In addition, silicon will undergo plastic deformation and current leakage at 600 ° C, resulting in extreme imbalance of the signal processing system and circuit. The surface acoustic wave pressure sensor technology based on quartz is quite mature, but its working temperature is generally -20°C-100°C, and it is not suitable for use in an environment higher than 200°C.

Chinese patent CN 1514219 provides a solid-state piezoresistive high-temperature resistant pressure sensor, which realizes temperature measurement in harsh environments above 200°C. However, this sensor still needs power supply and wires to transmit signals, so it is difficult to meet the high temperature requirements above 500°C. The Chinese patent CN101775657 relates to the zero temperature compensation cutting type for high temperature application of gallium lanthanum silicate, but does not specifically do in-depth work on the sensor for this crystal.

Contents of the invention

The invention aims to solve the technical problems existing in the prior art, and particularly innovatively proposes a surface acoustic wave high-temperature pressure sensor chip based on SOI and a piezoelectric film and a preparation method thereof.

In order to achieve the above object of the present invention, according to the first aspect of the present invention, the present invention provides a surface acoustic wave high-temperature pressure sensor chip based on SOI and piezoelectric thin film, which includes an SOI chip substrate, on which The silicon dioxide layer and the device layer thereon together constitute an SOI pressure-sensitive layer, a piezoelectric film is formed on the SOI pressure-sensitive layer, and an interdigital transducer and a reflective grid are formed on the piezoelectric film; Extending from the bottom surface of the SOI chip substrate to the pressure sensitive layer in the SOI chip substrate, a chamber for providing reference pressure when detecting pressure is formed. There may also be a second chip substrate under the SOI chip substrate, and a high vacuum sealed chamber is formed in the SOI chip substrate extending from the second chip substrate to the pressure sensitive layer.

The chip of the surface acoustic wave high-temperature pressure sensor of the present invention is small in size, can realize wireless transmission and reception when working in the radio frequency section, and has flexible measurement methods, so it has great application potential in the field of high-temperature pressure measurement.

In a preferred embodiment of the present invention, the SOI chip substrate and the pressure sensitive layer are formed by using SOI, and the resistivity of the SOI device layer is ≥5 kΩ. The prepared sensor chip has good high-temperature performance and ensures chip quality; the processing technology using SOI is mature and the yield is high.

In another preferred embodiment of the present invention, the piezoelectric film is a pure AlN piezoelectric film whose crystal grains are c-axis oriented or an AlN piezoelectric film doped with 10at%-43at% scandium element, so as to ensure the Detection effect.

In another preferred embodiment of the present invention, the interdigital transducer and the reflection grid are arranged in parallel above the piezoelectric film, and the material of the interdigital transducer and the reflection grid is the same material.

In another preferred embodiment of the present invention, the materials of the interdigital transducer and the reflection grid are aluminum, gold, molybdenum, platinum, iridium or their alloys, which can meet the requirements of various temperature sensors.

For example, aluminum is selected below 200°C; gold is selected below 600°C; molybdenum is selected below 800°C; platinum is selected below 1000°C; iridium is selected below 1200°C.

In another preferred embodiment of the present invention, a bottom electrode is formed between the pressure-sensitive layer and the piezoelectric film, and the bottom electrode may be drawn out and grounded, or may not be drawn out.

In another preferred embodiment of the present invention, a silicon dioxide flat layer may be formed above the pressure sensitive layer, or a periodic array of silicon dioxide three-dimensional structures and polycrystalline silicon three-dimensional structures may be formed above the pressure sensitive layer. Tiling layer, compensate and offset the pressure measurement error caused by the change of ambient temperature.

In order to achieve the above object of the present invention, according to a second aspect of the present invention, the present invention provides a method for preparing a surface acoustic wave high-temperature pressure sensor chip, which includes the following steps:

S1, providing SOI, the resistivity of the SOI device layer is ≥5kΩ;

S2, depositing and forming a piezoelectric film on the front side of the SOI;

S3, depositing an interdigital transducer and a reflective grid on the piezoelectric film;

S4, depositing and forming an insulating protection layer;

S5, photolithography, etch the insulating protective layer and the piezoelectric film layer, and open the window;

S6, depositing a conductive metal layer, photolithography, etching, forming a signal lead-out disk;

S7, photolithography, etching on the back of the SOI until the isolation layer of the SOI is exposed to form a pressure sensitive layer;

Step S8 with or without, bonding the back of the SOI to the second chip substrate to form a high-vacuum sealed chamber.

The preparation method of the present invention has a simple structure, and the surface acoustic wave high-temperature pressure sensor chip formed by it has a small volume, and its piezoelectric characteristics make it unnecessary to connect an external power supply, and can realize wireless transmission and reception in the radio frequency section, and the measurement method is flexible, so it is widely used in the field of high-temperature pressure measurement. It has great application potential.

In another preferred embodiment of the present invention, the step S2 is: depositing and forming a bottom electrode on the front side of the SOI, and then depositing and forming a piezoelectric film on the bottom electrode;

Or step S2 is: depositing and forming a silicon dioxide tiled layer on the front side of the SOI or depositing and forming a periodic array tiled layer with a silicon dioxide three-dimensional structure intersecting with a polysilicon three-dimensional structure, and then depositing on the front side of the said flat layer Deposit to form a piezoelectric film;

Or step S2 is: depositing and forming a silicon dioxide tiled layer on the front side of the SOI or depositing and forming a periodic array tiled layer with a silicon dioxide three-dimensional structure intersecting with a polysilicon three-dimensional structure, and then depositing and forming a bottom electrode. A piezoelectric thin film is deposited on the bottom electrode.

In a preferred embodiment of the present invention, an application structure utilizing a surface acoustic wave high-temperature pressure sensor chip based on SOI and a piezoelectric film adopts one of the following structures:

Structure 1: Simultaneously use two resonators or two delay lines in the form of dual-channel compensation to compensate for pressure measurement errors caused by changes in ambient temperature. The two resonators or two delay lines are due to different positions or different structural parameters. And have different temperature sensitive properties and/or pressure sensitive properties;

Structure 2: If there are two or more acoustic wave modes sensitive to temperature and pressure in the chip, and the two acoustic wave mode signal compensation methods are used to compensate and offset the pressure measurement error caused by the change of the ambient temperature, the The two acoustic modes have different temperature sensitivity and/or pressure sensitivity.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is the preparation flowchart of the surface acoustic wave high-temperature pressure sensor differential pressure chip based on SOI and piezoelectric film in a preferred embodiment of the present invention, wherein, Fig. 1-1 is the schematic diagram of SOI; Fig. 1-2 is in A schematic diagram of SOI front deposition to form a piezoelectric film; Fig. 1-3 is a schematic diagram of depositing and forming an interdigital transducer and a reflective grid on a piezoelectric film; Fig. 1-4 is a schematic diagram of depositing and forming an insulating protective layer; Figure 1-5 is a schematic diagram of opening a window to the bottom electrode; Figure 1-6 is a schematic diagram of opening a window to an interdigital transducer; Figure 1-7 is a schematic diagram of depositing a conductive metal layer; Figure 1-8 is a schematic diagram of the SOI backside Schematic diagram of etching until the isolation layer of SOI is exposed to form a pressure sensitive layer;

Fig. 2 is a flow chart of the preparation of the absolute pressure chip of the surface acoustic wave high-temperature pressure sensor based on SOI and piezoelectric film in a preferred embodiment of the present invention, wherein Fig. 2-1 is a schematic diagram of providing SOI; Fig. 2-2 is A schematic diagram of depositing and forming a piezoelectric film on the front side of SOI; Figure 2-3 is a schematic diagram of depositing and forming an interdigital transducer and a reflective gate on a piezoelectric film; Figure 2-4 is a schematic diagram of depositing and forming an insulating protective layer ; Fig. 2-5 is a schematic diagram of opening a window to the bottom electrode; Fig. 2-6 is a schematic diagram of opening a window to an interdigital transducer; Fig. 2-7 is a schematic diagram of depositing a conductive metal layer; A schematic diagram of etching the back of the SOI until the isolation layer of the SOI is exposed to form a pressure-sensitive layer; Figure 2-9 is a schematic diagram of bonding the back of the SOI to the second chip substrate to form a high-vacuum sealed chamber;

Fig. 3 is a flow chart of the preparation of the absolute pressure chip of the surface acoustic wave high temperature pressure sensor based on SOI and piezoelectric thin film in another preferred embodiment of the present invention (the difference from Fig. 2 is: the manufacturing process of the high vacuum sealed chamber The silicon-glass anode bonding process is no longer used, but the silicon-silicon bonding process is used), among which, Figure 3-1 is a schematic diagram of providing SOI; Figure 3-2 is a schematic diagram of forming a piezoelectric film deposited on the front side of SOI ; Figure 3-3 is a schematic diagram of depositing and forming an interdigital transducer and a reflective grid on a piezoelectric film; Figure 3-4 is a schematic diagram of depositing and forming an insulating protective layer; Figure 3-5 is opening a window to the bottom electrode Figure 3-6 is a schematic diagram of opening a window to an interdigital transducer; Figure 3-7 is a schematic diagram of depositing a conductive metal layer; Figure 3-8 is etching on the back of SOI until the isolation layer of SOI is exposed to form a pressure A schematic diagram of the sensitive layer; Figure 3-9 is a schematic diagram of bonding the back of the SOI to a silicon substrate to form a high-vacuum sealed chamber;

Fig. 4 (a) is a schematic structural view of a sensor chip without a bottom electrode in another preferred embodiment of the present invention; Fig. 4 (b) is a structural schematic view of a sensor chip with a bottom electrode in another preferred embodiment of the present invention;

Fig. 5 is a schematic diagram of a periodic array tiling layer in which a certain thickness of silicon dioxide three-dimensional structure and polysilicon three-dimensional structure are added to the sensor chip in a preferred embodiment of the present invention;

Fig. 6 is a schematic diagram of pressure measurement errors caused by the use of two resonator-type dual-channel compensation methods in a preferred embodiment of the present invention to compensate and offset changes in ambient temperature, wherein Fig. 6(a) shows that changes in the response signal only reflect the environment Schematic diagram of the structure of the resonator with temperature changes. Figure 6(b) is a schematic diagram of the structure of the resonator that reflects the dual effects of changes in the ambient temperature and pressure to be measured by changes in the response signal.

Reference signs:

1 SOI base layer; 2 SOI isolation layer; 3 SOI device layer; 4 Bottom electrode;

5 piezoelectric layer; 6 silicon dioxide insulating protective layer; 7 interdigital transducer; 8 interdigital transducer;

9 Interdigital transducer; 10 Signal lead-out plate.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", The orientation or positional relationship indicated by "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than Nothing indicating or implying that a referenced device or element must have a particular orientation, be constructed, and operate in a particular orientation should therefore not be construed as limiting the invention.

In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be mechanical connection or electrical connection, or two The internal communication of each element may be directly connected or indirectly connected through an intermediary. Those skilled in the art can understand the specific meanings of the above terms according to specific situations.

Fig. 4(a) is a cross-sectional view of the surface acoustic wave high-temperature pressure sensor chip of the first preferred embodiment of the present invention. The size of each area is only schematically shown in the figure, and the specific size can be designed according to the requirements of device parameters .

It can be seen from Fig. 4(a) that the surface acoustic wave high-temperature pressure sensor chip includes: an SOI chip substrate on which a pressure-sensitive layer is formed. In this embodiment, SOI (Silicon On Insulator, silicon on insulator) is used to prepare A pressure sensitive layer is formed, and the resistivity of the SOI device layer is greater than or equal to 5kΩ. The isolation layer 2 (silicon dioxide) in SOI and the device layer 3 thereon form the SOI pressure sensitive layer together, and the base layer 1 under the SOI isolation layer is the SOI chip base, which extends from the bottom surface of the SOI chip base to the SOI chip base in the SOI chip base. The pressure sensitive layer is formed with a cavity that provides a reference pressure when detecting pressure.

A piezoelectric thin film is formed on the pressure sensitive layer. In this embodiment, the piezoelectric thin film is a pure AlN piezoelectric layer 5 with c-axis oriented crystal grains or an AlN piezoelectric thin film 5 doped with 10at%-43at% scandium. Interdigital transducers 7, 8, 9 and reflective grids are formed on the piezoelectric film. The interdigital transducers 7, 8, 9 and the reflection grid are arranged in parallel above the piezoelectric film, and the materials of the interdigital transducers and the reflection grid are the same material. Preferably, the material of the interdigital transducer and the reflection grid is aluminum, gold, molybdenum, platinum, iridium or alloys thereof.

In this implementation manner, the interdigital transducer and the reflective grating may form a surface acoustic wave single-ended resonator, a surface acoustic wave double-ended resonator, or a surface acoustic wave delay line. Specifically, the structure of the surface acoustic wave single-ended resonator is to place an interdigital transducer between two reflection gratings, and the structure of the surface acoustic wave double-terminal resonator is to place two interdigital transducers between two reflection gratings. Two reflection gratings are placed between two interdigital transducers or two interdigital transducers, and the structure of the surface acoustic wave delay line is that two or more interdigital transducers are arranged in parallel.

In this embodiment, a chamber that provides a reference pressure when detecting pressure is formed in the SOI chip substrate extending from the bottom surface of the substrate to the pressure sensitive layer. As shown in Figures 1-8, the chamber is open in the differential pressure structure structure, not a sealed chamber. In another preferred embodiment of the present invention, under the SOI chip substrate is a second chip substrate, and a high vacuum seal that provides a reference pressure when detecting pressure is formed between the SOI chip substrate extending from the second chip substrate to the pressure sensitive layer The chamber, as shown in Figure 2-9, is a high vacuum sealed chamber in the absolute pressure structure.

The present invention provides a method for preparing a surface acoustic wave high-temperature pressure sensor chip based on SOI and a piezoelectric film, the differential pressure structure shown in Figure 1-8, which includes the following steps:

S1, as shown in FIG. 1-1, provides SOI, and the resistivity of the SOI device layer is ≥5kΩ.

S2, as shown in Figure 1-2, a piezoelectric film is deposited on the front side of the SOI to form a piezoelectric film. In this embodiment, the piezoelectric film is a pure AlN piezoelectric film whose crystal grains are c-axis oriented or doped with 10at%- AlN piezoelectric film with 43at% scandium element.

S3, as shown in Fig. 1-3, deposit and form interdigital transducers and reflective grids on the piezoelectric film, and finally form the structure as shown in Fig. 4(a).

In another preferred embodiment of the present invention, as shown in Fig. 1-2, step S2 is to deposit and form a bottom electrode on the front side of the SOI, and the material of the bottom electrode is preferably Ti/Pt material, and deposit Piezoelectric film is formed by deposition; as shown in Figure 1-3, interdigital transducers and reflective grids are deposited on the piezoelectric film, and the final structure is shown in Figure 4(b). The material of the interdigital transducer and the reflection grid is aluminum, gold, molybdenum, platinum, iridium or their alloys. In this embodiment, the material of the interdigital transducer and the reflection grid is preferably molybdenum.

S4, as shown in FIGS. 1-4 , deposit and form an insulating protection layer 6 , and the specific material is preferably silicon dioxide.

S5, as shown in Figures 1-5 and 1-6, photolithography, etch the insulating protective layer and the piezoelectric film layer; in this embodiment, Figure 1-5 shows opening the window to the bottom electrode, Figure 1-6 shows Open the window to the interdigital transducer.

S6, as shown in FIGS. 1-7 , deposit a conductive metal layer, perform photolithography, and etch to form a signal lead-out plate 10, and the material of the lead-out plate is metal, preferably gold.

S7, photolithography, as shown in FIG. 1-8, etching on the back of the SOI until the isolation layer of the SOI is exposed to form a pressure sensitive layer.

Fig. 2-1 to Fig. 2-9 are flow charts of the absolute pressure chip of the surface acoustic wave high temperature pressure sensor based on SOI and piezoelectric film in a preferred embodiment of the present invention, which includes the following steps:

S1, as shown in Figure 2-1, provides SOI, and the resistivity of the SOI device layer is ≥5kΩ.

S2, as shown in Figure 2-2, a piezoelectric film is deposited on the front side of the SOI to form a piezoelectric film. In this embodiment, the piezoelectric film is a pure AlN piezoelectric film whose crystal grains are c-axis oriented or doped with 10at%- AlN piezoelectric film with 43at% scandium element.

S3, as shown in Figure 2-3, depositing and forming an interdigital transducer and a reflective grid on the piezoelectric film; in another preferred embodiment of the present invention, as shown in Figure 2-2, step S2 is The bottom electrode is deposited on the front side of SOI, and the material of the bottom electrode is preferably Ti/Pt material, and a piezoelectric film is deposited on the bottom electrode; as shown in Figure 1-3, a piezoelectric film is deposited on the piezoelectric film Form the interdigital transducer and the reflective grid, the materials of the interdigital transducer and the reflective grid are aluminum, gold, molybdenum, platinum, iridium or their alloys, in this embodiment, the material of the interdigital transducer and the reflective grid Molybdenum is preferred.

S4, as shown in FIG. 2-4, deposit and form an insulating protective layer, and the specific material is preferably silicon dioxide.

S5, as shown in Figures 2-5 and 2-6, photolithography, etch the insulating protective layer and the piezoelectric film layer; in this embodiment, Figure 2-5 shows opening the window to the bottom electrode, Figure 2-6 shows Open the window to the interdigital transducer.

S6, as shown in FIG. 2-7, deposit a conductive metal layer, perform photolithography, and etch to form a signal lead-out disk, and the material of the lead-out disk is metal, preferably gold.

S7, as shown in FIG. 2-8, photolithography, etch on the back of the SOI until the isolation layer of the SOI is exposed to form a pressure sensitive layer.

S8, as shown in FIGS. 2-9 , bonding the back of the SOI to the second chip substrate to form a high-vacuum sealed chamber. In this embodiment, the second chip substrate used is glass. In this embodiment, the bonding is carried out under vacuum conditions, and the specific vacuum level used can be determined according to specific experiments, preferably high vacuum.

Figure 3-1 to Figure 3-9 are flow charts of the absolute pressure chip of the surface acoustic wave high temperature pressure sensor based on SOI and piezoelectric thin film in another preferred embodiment of the present invention, the difference from Figure 2-9 is that: The manufacturing process of the vacuum-sealed chamber no longer uses the silicon-glass anode bonding process, but the silicon-silicon bonding process, as shown in Figure 3-9.

As shown in Figure 5, a silicon dioxide tile layer is first deposited on the front of the SOI, or a periodic array tile layer with a silicon dioxide three-dimensional structure intersecting with a polysilicon three-dimensional structure is deposited on the front side of the SOI, and then other layers are formed. Structure. For example, the bottom electrode and the piezoelectric film are deposited to form the bottom electrode and the piezoelectric film, and the interdigital transducer and the reflective grid are formed by depositing on the piezoelectric film.

In this implementation manner, the interdigital transducer and the reflective grating may form a surface acoustic wave single-ended resonator, a surface acoustic wave double-ended resonator, or a surface acoustic wave delay line.

Fig. 6(a) and Fig. 6(b) are schematic diagrams of a preferred embodiment of the present invention using a dual-channel compensation method in the form of two resonators to compensate and offset pressure measurement errors caused by changes in ambient temperature. In this embodiment, a dual-channel compensation method in the form of two delay lines may also be used to compensate and offset pressure measurement errors caused by changes in ambient temperature. Due to the different structural parameters, the change of the resonator response signal in Figure 6(a) only reflects the change of the ambient temperature, while the change of the resonator response signal in Figure 6(b) reflects the dual effects of the change of the ambient temperature and the change of the pressure to be measured .

If there are two or more acoustic wave modes sensitive to temperature and pressure in the chip, the two acoustic wave mode signal compensation methods can also be used at the same time to compensate and offset the pressure measurement error caused by the change of the ambient temperature. Each acoustic wave mode has different temperature sensitivity and/or pressure sensitivity.

The surface acoustic wave high temperature pressure sensor chip based on SOI and piezoelectric thin film of the invention can realize pressure measurement under high temperature environment. In this embodiment, the piezoelectric film is deposited on the pressure-sensitive layer by magnetron sputtering technology, the interdigital transducer and the reflective grid are fabricated on the piezoelectric film by MEMS technology, and the sensor chip utilizes piezoelectric effect and inverse pressure Electric effects carry out excitation and reception of surface acoustic waves. The interdigital transducer excites the surface acoustic wave on the surface of the piezoelectric film, and the surface acoustic wave propagates to the reflection grids on both sides, propagates to the position of the reflection grid and is reflected back. The reflected surface acoustic wave is converted into an electromagnetic wave signal again through the interdigital transducer, that is, the response signal. When the pressure to be measured acts on the piezoelectric film and the pressure-sensitive layer, the composite film is deformed, the propagation speed of the surface acoustic wave changes, and the response signal changes. The electromagnetic wave response signal is analyzed by specific signal processing to realize the pressure Measurement. The sensor chip can be made into a differential pressure structure, or can be made into an absolute pressure structure through a vacuum-tight bonding process. The invention has the advantages of simple structure, small size, light weight and high precision, and can be applied to the measurement of pressure parameters in high-temperature environments such as aerospace, petrochemical and nuclear industries.

It should be noted that the small boxes below the figures in the drawings of the specification are material descriptions.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples" or "some examples" mean specific features described in connection with the embodiment or example, A structure, material or characteristic is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. A kind of 1. surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane, it is characterised in that including：

   It is quick that soi chip substrate, the silicon dioxide layer in the soi chip substrate and device layer thereon collectively form SOI pressure Layer is felt, formed with piezoelectric membrane on the SOI pressure sensitive layers, formed with interdigital transducer and anti-on the piezoelectric membrane Penetrate grid；

   Reference is provided when extending to pressure sensitive layer formed with detection pressure from soi chip substrate bottom surface in soi chip substrate The chamber of pressure.
2. 2. the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane, its feature exist as claimed in claim 1 In resistivity >=5k Ω of SOI device layer；

   And/or the piezoelectric membrane is pure AlN piezoelectric membrane or doping 10at%-43at% scandium element of the crystal grain in c-axis orientation AlN piezoelectric membranes.
3. 3. the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane, its feature exist as claimed in claim 1 In interdigital transducer and reflecting grating are set in parallel above piezoelectric membrane, and the interdigital transducer and reflection grid material are same A kind of material.
4. 4. the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane as described in claim 1 or 3, it is special Sign is that the material of the interdigital transducer and reflecting grating is aluminium, gold, molybdenum, platinum, iridium or its alloy.
5. 5. the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane, its feature exist as claimed in claim 1 In being the second chip base under the soi chip substrate, pressure extended to from the second chip base in soi chip substrate Formed with high vacuum seal chamber between sensitive layer.
6. 6. the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane, its feature exist as claimed in claim 1 In can draw and be grounded, can also be not brought up formed with hearth electrode, the hearth electrode between pressure sensitive layer and piezoelectric membrane.
7. 7. the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane as described in claim 1 or 6, it is special Sign is, formed with silica tiling layer between pressure sensitive layer and hearth electrode, or in pressure sensitive layer and hearth electrode Between the cyclic array formed with silica stereochemical structure and polysilicon stereochemical structure cross-distribution tile layer；Or pressing Formed with silica tiling layer between power sensitive layer and piezoelectric membrane, or formed between pressure sensitive layer and piezoelectric membrane There is the cyclic array tiling layer of silica stereochemical structure and polysilicon stereochemical structure cross-distribution.
8. A kind of 8. method for preparing the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane, it is characterised in that Comprise the following steps：

   S1, there is provided SOI, resistivity >=5k Ω of SOI device layer；

   S2, piezoelectric membrane is formed in the deposit of SOI fronts；

   S3, deposited on the piezoelectric membrane and form interdigital transducer and reflecting grating；

   S4, deposit form insulating protective layer；

   S5, photoetching, etch insulating protective layer and piezoelectric thin film layer, windowing；

   S6, conductive metal layer is deposited, photoetching, etching, signal is formed and draws disk；

   S7, photoetching, in the SOI back-etchings, until the separation layer on SOI exposes to form pressure sensitive layer；

   With or without step S8, the SOI back sides and the second chip base are bonded together to form into high vacuum seal chamber.
9. 9. the side of the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane is prepared as claimed in claim 8 Method, it is characterised in that the step S2 is：Hearth electrode is formed in the deposit of SOI fronts, is then formed sediment on the hearth electrode Product forms piezoelectric membrane；

   Or step S2 is：Silica tiling layer is formed in the deposit of SOI fronts or deposit forms silica solid The cyclic array tiling layer of structure and polysilicon stereochemical structure cross-distribution, then deposit forms pressure on the tiling layer Conductive film；

   Or step S2 is：Silica tiling layer is formed in the deposit of SOI fronts or deposit forms silica solid The cyclic array tiling layer of structure and polysilicon stereochemical structure cross-distribution, then deposit forms hearth electrode, in bottom electricity Deposit forms piezoelectric membrane on pole.
10. A kind of 10. application knot of the surface acoustic wave chip of high-temp pressure sensor based on SOI and piezoelectric membrane described in claim 1 Structure, it is characterised in that using one of following structure：

    Structure one：Simultaneously counteracting environment temperature is compensated using the two-channel compensation mode of two resonators or two delay line forms Change caused by pressure measurement error, described two resonators or two delay lines have because position is different or structural parameters are different There are different temperature sensitivity energy and/or pressure-sensitivity characteristic；

    Structure two：As two or more the sound wave modal sensitive to temperature and pressure in the chip be present, make simultaneously Pressure measurement error caused by compensating the change for offsetting environment temperature with two kinds of sound wave modal signal compensation modes, described two sound wave moulds State has different temperature sensitivity energy and/or pressure-sensitivity characteristic.