CN107631827A - A kind of surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane and preparation method thereof - Google Patents

Abstract

The present invention proposes a kind of surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane and preparation method thereof, and it includes：Silicon crystal unit chip base, the silicon crystal unit chip base includes first surface and second surface, chamber is internally provided with the silicon crystal unit chip base, the chamber has opening or the second chip base by being bonded to silicon crystal unit chip base to seal and form high vacuum seal chamber in silicon crystal unit chip base second surface；Silicon crystal unit chip base on the chamber is pressure sensitive film, formed with piezoelectric membrane on the pressure sensitive film, formed with interdigital transducer and reflecting grating on the piezoelectric membrane.The surface acoustic wave chip of high-temp pressure sensor small volume based on silicon crystal unit and piezoelectric membrane 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 Silicon Wafer and Piezoelectric Film and 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 silicon wafers and piezoelectric films 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 problems existing in the prior art, and particularly innovatively proposes a surface acoustic wave high-temperature pressure sensor chip based on a silicon wafer 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 a silicon wafer and a piezoelectric film, which includes a silicon wafer chip substrate, said The silicon wafer chip base includes a first surface and a second surface, and a cavity is arranged inside the silicon wafer chip base, and the cavity has an opening on the second surface of the silicon wafer chip base or is bonded to the silicon wafer. The second chip substrate on the second surface of the chip substrate is sealed to form a high-vacuum sealed chamber; the silicon wafer chip substrate above the chamber is a pressure-sensitive film, and a piezoelectric film is formed on the pressure-sensitive film. An interdigital transducer and a reflective grid are formed on the piezoelectric film.

The high-temperature pressure sensor chip based on silicon wafer and piezoelectric thin film surface acoustic wave of the present invention is small in size, works in the radio frequency range, can realize wireless transmission and reception, and has flexible measurement methods, so it has very great application potential in the field of high-temperature pressure measurement.

In a preferred embodiment of the present invention, the resistivity of the silicon wafer chip substrate is ≥5 kΩ. The prepared sensor has good high-temperature performance and ensures chip quality; the processing technology of the silicon wafer is simple and the yield is high.

In another preferred embodiment of the present invention, the piezoelectric thin film is a pure AlN piezoelectric thin film whose crystal grains are c-axis oriented or an AlN piezoelectric thin film doped with 10at%-43at% scandium element. Ensure the temperature detection effect at high temperature.

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 interdigital transducer and the reflection grid are made of 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 alloys thereof. It 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 film and the piezoelectric film, and the bottom electrode may or may not be drawn out to ground.

In another preferred embodiment of the present invention, a silicon dioxide flat layer is formed between the pressure-sensitive film and the bottom electrode, or a silicon dioxide three-dimensional structure and a polysilicon three-dimensional structure are formed between the pressure-sensitive film and the bottom electrode. Periodic array tiling layers with cross-distributed structures; or a silicon dioxide tiling layer is formed between the pressure-sensitive film and the piezoelectric film, or a silicon dioxide three-dimensional structure and the piezoelectric film are formed between the pressure-sensitive film and the piezoelectric film A periodic array of tiled layers with polysilicon three-dimensional structures cross-distributed. Compensation counteracts pressure measurement errors caused by changes in ambient temperature.

An insulating protective layer is formed on the interdigital transducer and the reflective grid to protect the device from insulation.

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 based on a silicon wafer and a piezoelectric film, which includes the following steps:

S1, providing a silicon wafer chip substrate, the resistivity of the silicon wafer chip substrate being ≥ 5kΩ;

S2, forming a cavity by deep etching on the backside of the silicon wafer chip substrate, and the chip substrate above the cavity is a pressure sensitive film;

S3, depositing and forming a piezoelectric thin film layer on the front surface of the silicon wafer chip substrate;

S4, depositing and forming an interdigital transducer and a reflective grid on the piezoelectric thin film layer;

S5, depositing and forming an insulating protection layer;

S6, photolithography, etching the insulating protective layer and the piezoelectric film layer, and opening the window;

S7, depositing a conductive metal layer, photolithography, etching, forming a signal lead-out disk;

With or without step S8, bonding the back side of the silicon wafer chip substrate to the second chip substrate to form a high vacuum sealed chamber.

The preparation method of the present invention is simple in structure, and the surface acoustic wave high-temperature pressure sensor chip formed by it is small in size, and its piezoelectric characteristics make it need no external power supply, work in the radio frequency section, can realize wireless transmission and reception, and the measurement method is flexible, so in high-temperature pressure measurement The field has great application potential.

In a preferred embodiment of the present invention, the step S3 is: depositing and forming a bottom electrode on the front surface of the silicon wafer chip substrate, and depositing and forming a piezoelectric thin film layer on the bottom electrode;

Or step S3 is: depositing a silicon dioxide flat layer on the front surface of the silicon wafer chip substrate, or depositing a periodic array of silicon dioxide three-dimensional structures and polysilicon three-dimensional structures intersecting distribution on the front surface of the silicon wafer chip substrate Tiled layers, and then deposited to form a piezoelectric film layer;

Or step S3 is: depositing a silicon dioxide flat layer on the front surface of the silicon wafer chip substrate, or depositing a periodic array of silicon dioxide three-dimensional structures and polysilicon three-dimensional structures intersecting distribution on the front surface of the silicon wafer chip substrate A flat layer is then deposited to form a bottom electrode, and a piezoelectric thin film layer is deposited on the bottom electrode.

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 a flow chart of the preparation of a surface acoustic wave high-temperature pressure sensor differential pressure chip based on a silicon wafer and a piezoelectric thin film in the first preferred embodiment of the present invention;

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 the silicon wafer and the piezoelectric film in the second preferred embodiment of the present invention;

Fig. 3 is the flow chart of the preparation of the absolute pressure chip of the surface acoustic wave high-temperature pressure sensor based on the silicon wafer and the piezoelectric film in the third preferred embodiment of the present invention (the difference from Fig. 2 is: the making of the high-vacuum sealed chamber The process no longer uses the silicon-glass anode bonding process, but the silicon-silicon bonding process);

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;

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

Fig. 6 is a schematic diagram of a preferred embodiment of the present invention using a dual-channel compensation method in the form of two resonators to compensate for pressure measurement errors caused by changes in ambient temperature.

Reference signs:

1 silicon wafer chip substrate; 2 monocrystalline silicon pressure sensitive layer; 3 silicon dioxide; 4 bottom electrode;

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

9 interdigital transducers; 10 signal lead-out discs.

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 is a cross-sectional view of a surface acoustic wave high-temperature pressure sensor chip based on a silicon wafer and a piezoelectric thin film in the first preferred embodiment of the present invention, in which the dimensions of each region are only schematically shown, and the specific dimensions can be determined according to The requirements of the device parameters are designed.

It can be seen from Fig. 4 that the surface acoustic wave high-temperature pressure sensor chip includes a silicon wafer chip substrate 1, and the silicon wafer chip substrate 1 includes a first surface (the upper surface in the figure, that is, the front side) and a second surface (the lower surface in the figure, That is, the back side), a chamber is arranged inside the silicon wafer chip substrate, and the chamber has an opening on the second surface of the silicon wafer chip substrate or is sealed to the chip by a second chip substrate bonded to the silicon wafer chip substrate A high-vacuum sealed chamber is formed inside the substrate; the silicon wafer chip substrate above the chamber is a pressure-sensitive film (monocrystalline silicon pressure-sensitive layer 2). In this embodiment, the resistivity of the silicon wafer chip substrate is greater than or equal to 5 kΩ.

A piezoelectric thin film is formed on the pressure sensitive film. 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 placed in parallel above the piezoelectric film, and the interdigital transducers and the reflection grid are made of 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 embodiment, only the interdigital transducer is shown in FIG. 4 , and the reflective grid can be arranged on the piezoelectric film according to a common method in the art.

Fig. 1 is a flow chart of the preparation of a surface acoustic wave high-temperature pressure sensor differential pressure chip based on a silicon wafer and a piezoelectric film in a preferred embodiment of the present invention, which includes the following steps:

S1, as shown in FIG. 1-1 , provides a high-resistance silicon wafer chip substrate, and the resistivity of the high-resistance silicon wafer chip substrate is ≥5 kΩ.

S2, as shown in FIG. 1-2, deep etching forms a cavity on the backside of the high-resistance silicon wafer chip substrate, and the chip substrate above the cavity is a pressure-sensitive film.

S3, as shown in Figures 1-3, deposit and form a piezoelectric thin film layer on the front surface of the silicon wafer chip substrate. In this embodiment, the piezoelectric thin film is a pure AlN piezoelectric thin film or doped AlN piezoelectric film doped with 10at%-43at% scandium element.

S4, as shown in Figure 1-4, deposit and form the interdigital transducer and the reflection grid on the piezoelectric film layer, the material of the interdigital transducer and the reflection grid is aluminum, gold, molybdenum, platinum, iridium or Its alloy, in this embodiment, the material of the interdigital transducer and the reflection grid is preferably molybdenum.

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 placed in parallel.

In another preferred embodiment of the present invention, as shown in Figures 1-3, step S3 is to form a bottom electrode by depositing on the front surface of the silicon wafer chip substrate, and the material of the bottom electrode is preferably Ti/Pt material. A piezoelectric thin film layer is deposited on the bottom electrode; as shown in Figure 1-4, an interdigital transducer and a reflective grid are formed by deposition on the piezoelectric thin film layer.

S5, as shown in FIGS. 1-5 , deposit and form an insulating protection layer 6 , and the specific material is preferably silicon dioxide.

S6, as shown in FIG. 1-6, photolithography, etch the insulating protection layer in S5 and the piezoelectric film layer in S4, and open a window to the bottom electrode layer.

S7, as shown in FIG. 1-7, photolithography, etch the insulating protective layer in S5, and open a window to the interdigital transducer layer.

S8, as shown in FIGS. 1-8 , depositing a conductive metal layer, photolithography, and etching to form a signal lead-out plate 10, the material of which is metal, preferably gold.

Fig. 2 is a flow chart of the preparation of an absolute pressure chip of a surface acoustic wave high-temperature pressure sensor based on a silicon wafer and a piezoelectric film in a preferred embodiment of the present invention, which includes the following steps:

S1, as shown in FIG. 2-1 , provides a high-resistance silicon wafer chip substrate, and the resistivity of the silicon wafer chip substrate is ≥5kΩ.

S2, as shown in FIG. 2-2, deep etching forms a cavity on the backside of the high-resistance silicon wafer chip substrate;

S3, as shown in FIG. 2-3 , bonding the back side of the silicon wafer 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 performed under vacuum conditions. The specific vacuum level used can be determined according to specific experiments, preferably high vacuum.

S4, as shown in Figures 2-4 and 2-5, after the pressure-sensitive film is prepared by dry etching or wet etching the front side of the silicon wafer chip substrate, a piezoelectric film layer is deposited on its surface .

S5, as shown in Figure 2-6, deposit and form interdigital transducers and reflective grids on the piezoelectric film layer, the materials of interdigital transducers and reflective grids are aluminum, gold, molybdenum, platinum, iridium or Its alloy, in this embodiment, the material of the interdigital transducer and the reflection grid is preferably molybdenum.

In another preferred embodiment of the present invention, as shown in Figures 2-4 and 2-5, step S4 is to dry-etch or wet-etch the front side of the silicon wafer chip substrate to prepare a pressure-sensitive film, The bottom electrode is formed by depositing on the front side of the silicon wafer chip substrate, and the material of the bottom electrode is preferably Ti/Pt material, and a piezoelectric thin film layer is deposited on the bottom electrode; as shown in Figure 2-6, in An interdigital transducer and a reflective grid are deposited on the piezoelectric thin film layer.

S6, as shown in FIG. 2-7, deposit and form an insulating protection layer, and the specific material is preferably silicon dioxide.

S7, as shown in FIG. 2-8, photolithography, etch the insulating protection layer in S6 and the piezoelectric thin film layer in S4, and open a window to the bottom electrode layer.

S8, as shown in FIG. 2-9, photolithography, etching the insulating protection layer in S6, and opening a window to the interdigital transducer layer.

S9, as shown in FIG. 2-10, deposit a conductive metal layer, perform photolithography, and etch to form a signal lead-out disk. The material of the lead-out disk is metal, preferably gold.

Fig. 3 is a flow chart of the preparation of an absolute pressure chip of a surface acoustic wave high-temperature pressure sensor based on a silicon wafer and a piezoelectric thin film in another preferred embodiment of the present invention. The difference from Fig. 2 is: a high vacuum sealed chamber The manufacturing process no longer uses the silicon-glass anodic bonding process, but the silicon-silicon bonding process.

As shown in Figure 5, a silicon dioxide flat layer is first deposited on the front side of the silicon wafer chip substrate, or a periodic pattern of intersecting distribution of the silicon dioxide three-dimensional structure and the polysilicon three-dimensional structure is formed on the front surface of the silicon wafer chip substrate. Arrays tile layers to form other structures. For example, redeposit to form a bottom electrode, deposit and form a piezoelectric film layer on the bottom electrode, deposit and form an interdigital transducer and a reflective grid on the piezoelectric film layer; or redeposit to form a piezoelectric film layer An electric thin film layer is deposited on the piezoelectric thin film layer to form an interdigital transducer and a reflective grid.

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 is a schematic diagram of a preferred embodiment of the present invention using a dual-channel compensation method in the form of two resonators to compensate for 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 simultaneously to compensate and offset pressure measurement errors caused by changes in ambient temperature. Due to the different structures of the two resonators, the change of the response signal of the resonator in Fig. 6 (a) only reflects the change of the ambient temperature, while the change of the response signal of the resonator in Fig. 6 (b) reflects the change of the ambient temperature and the Dual action of pressure changes. 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 purpose of the present invention is to provide a surface acoustic wave high-temperature pressure sensor chip based on a high-resistance silicon wafer that can work in a high-temperature environment, solve the problems of power supply and lead degradation in high-temperature pressure measurement, and realize pressure monitoring in a high-temperature environment.

In this embodiment, a piezoelectric thin film is deposited on the pressure sensitive film, an interdigital transducer and a reflective grid are fabricated on the piezoelectric thin film, and the surface acoustic wave is performed on the piezoelectric thin film by using the piezoelectric effect and the inverse piezoelectric effect. Inspire and receive. 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 structure can be made into a differential pressure structure, or can be made into an absolute pressure structure through a high vacuum sealing bonding process. The chip of 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 that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present 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 silicon crystal unit and piezoelectric membrane, it is characterised in that including：

   Silicon crystal unit chip base, the silicon crystal unit chip base includes first surface and second surface, in the silicon wafer element chip Base internal is provided with chamber, and the chamber has opening or by being bonded to silicon crystal unit core in silicon crystal unit chip base second surface Second chip base of piece substrate second surface seals to form high vacuum seal chamber；

   Silicon crystal unit chip base on the chamber is pressure sensitive film, formed with piezoelectric membrane on the pressure sensitive film, Formed with interdigital transducer and reflecting grating on the piezoelectric membrane.
2. 2. the surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane as claimed in claim 1, it is special Sign is, resistivity >=5k Ω of silicon crystal unit chip base；

   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 silicon crystal unit and piezoelectric membrane as claimed in claim 1, it is special Sign is that the interdigital transducer and reflecting grating be arranged in parallel above piezoelectric membrane, and the interdigital transducer and reflecting grating are Same material.
4. 4. the surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane as described in claim 1 or 3, its It is characterised by, 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 silicon crystal unit and piezoelectric membrane as claimed in claim 1, it is special Sign is, can draw ground connection formed with hearth electrode, the hearth electrode between pressure sensitive film and piezoelectric membrane, can not also draw Go out.
6. 6. the surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane as described in claim 1 or 5, its It is characterised by, formed with silica tiling layer between pressure sensitive layer and hearth electrode, or in pressure sensitive layer and bottom electricity Cyclic array tiling layer formed with silica stereochemical structure and polysilicon stereochemical structure cross-distribution between pole；

   Either formed with silica tiling layer or in pressure sensitive layer and piezoelectricity between pressure sensitive layer and piezoelectric membrane Cyclic array tiling layer formed with silica stereochemical structure and polysilicon stereochemical structure cross-distribution between film；With/ Or formed with insulating protective layer on interdigital transducer and reflecting grating.
7. 7. the surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane as claimed in claim 1, it is special Sign is, 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 because placement location is different or structural parameters are different And there is different temperature sensitivity energy and/or pressure-sensitivity characteristic；

   Structure two：As exist in the surface acoustic wave chip of high-temp pressure sensor two or more to temperature and pressure Sensitive sound wave modal, while surveyed caused by compensating the change of counteracting environment temperature using two kinds of sound wave modal signal compensation modes Difference is held up, described two sound wave modals have different temperature sensitivity energy and/or pressure-sensitivity characteristic.
8. 8. a kind of method for preparing the surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane, its feature exist In comprising the following steps：

   S1, there is provided silicon crystal unit chip base, resistivity >=5k Ω of the silicon crystal unit chip base；

   S2, the chip base on the back side deep etching formation chamber of the silicon crystal unit chip base, the chamber is pressure Sensitive membrane；

   S3, piezoelectric thin film layer is formed in the front deposit of the silicon crystal unit chip base；

   S4, deposited on the piezoelectric thin film layer and form interdigital transducer and reflecting grating；

   S5, deposit form insulating protective layer；

   S6, photoetching, etch insulating protective layer and piezoelectric thin film layer, windowing；

   S7, conductive metal layer is deposited, photoetching, etching, signal is formed and draws disk；

   With or without step S8, the silicon crystal unit chip base back side and the second chip base are bonded together to form into high vacuum seal Chamber.
9. 9. the surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit and piezoelectric membrane is prepared as claimed in claim 8 Method, it is characterised in that the step S3 is：Hearth electrode is formed in the deposit of silicon crystal unit chip base front, at the bottom Deposit forms piezoelectric thin film layer on electrode；

   Or step S3 is：Silica tiling layer is formed in the deposit of silicon crystal unit chip base front, or in silicon crystal unit The cyclic array that the deposit of chip base front forms silica stereochemical structure and polysilicon stereochemical structure cross-distribution tiles Layer, then deposit form piezoelectric thin film layer；

   Or step S3 is：Silica tiling layer is formed in the deposit of silicon crystal unit chip base front, or in silicon crystal unit The cyclic array that the deposit of chip base front forms silica stereochemical structure and polysilicon stereochemical structure cross-distribution tiles Layer, then deposit form hearth electrode, are deposited on the hearth electrode and form piezoelectric thin film layer.
10. 10. the method for the surface acoustic wave chip of high-temp pressure sensor based on silicon crystal unit is prepared as claimed in claim 8 or 9, Characterized in that, in the step S3, pressure is thinned in the front dry etching or wet etching of silicon crystal unit chip base Piezoelectric thin film layer is formed after sensitive membrane in its surface deposition again.