32 results about "Piezoresistive accelerometer" patented technology

An arrangement that converts mechanical energy into electrical energy employs a base member and a cantilever member coupled thereto. The cantilever member has two piezoelectric layers with an air space therebetween. A proof mass is coupled to the cantilever member distal from the base member. The first and second piezoelectric layers are formed of lead zirconate titanate (PZT), and the output voltage of the cantilever member is proportional to the height of the air gap. A piezoresistive accelerometer that is useful for measuring mechanical vibration has a suspension beam and a piezoresistive layer be separated from the suspension beam. A method of monitoring an acoustic vibration utilizes a piezoresistive element having an air-spaced cantilever formed of a piezoelectric material in the vicinity of the system to be monitored and obtains an alternating voltage form the air-spaced cantilever of the piezoresistive element.

The invention discloses a processing method of an integrated piezoresistive accelerometer and a pressure meter which are based on a prefabricated cavity SOI (silicon on insulator) substrate. The accelerometer comprises an elastic beam-mass block structure with a force sensitive resistor, and the pressure meter comprises a pressure sensitive diaphragm with a force sensitive resistor. The method is as follows: preparing dosage concentration resistor stripes as the force sensitive resistor and a temperature sensitive resistor on a device layer of the SOI substrate; processing a metal wire layer and a passivation layer; deeply etching to the prefabricated cavity, releasing the elastic beam-mass block structure; and bonding a cover sheet cover to protect the movable structure. Compared with the prior art, according to the processing method, the symmetrical elastic beam-mass block structure with precise size can be processed by a single-surface and single-step process, a monocrystalline silicon sensitive resistor and the temperature sensitive resistor of the accelerometer and the pressure meter can be processed, the device sensitivity is high, the process repeatability is good, a vacuum packaging step of a traditional absolute-pressure pressure meter is omitted; and the prepared elastic beam-mass block structure is universal.

This invention relates to a composite beam pressure drag accelerometer; belong to micro machine electronic technology. This invention solves existing problem of that structure of high g accelerometer can not satisfy characteristic request of first order's high inherent rate, wide frequency response scope and worse shock resistance. this accelerometer includes silica-based support carriage shell, spring beam, quality piece that through spring beam overhung in middle of carriage shell, varistor diffused on tip of spring beam. Silica-based support carriage shell undersurface by electrostatic link glass bottom cap. Quality piece is composed by frame body and quality core that through bridge hooked to frame body.

A manufacturing process of a semiconductor piezoresistive accelerometer includes the steps of: providing a wafer of semiconductor material; providing a membrane in the wafer over a cavity; rigidly coupling an inertial mass to the membrane; and providing, in the wafer, piezoresistive transduction elements, that are sensitive to strains of the membrane and generate corresponding electrical signals. The step of coupling is carried out by forming the inertial mass on top of a surface of the membrane opposite to the cavity. The accelerometer is advantageously used in a device for monitoring the pressure of a tire of a vehicle.

An accelerometer and a method of fabricating an integrated accelerometer comprises the steps of providing an SOI wafer with a selected resistivity to eliminate any need for additional doping of the SOI wafer, providing a single mask on the SOI wafer, and simultaneously defining all components of the accelerometer in the SOI wafer without using any pn-junctions to define any piezoresistive components and to provide the same resistivity of all components. The step of simultaneously defining all components of the accelerometer in the SOI wafer comprises defining all components of a linear or angular accelerometer.

The invention relates to a piezoresistive silicon-micro-accelerometer, in particular to the piezoresistive silicon-micro-accelerometer which can reduce temperature drift. The temperature property of the piezoresistive silicon-micro-accelerometer is improved, and the temperature drift is reduced. The accelerometer comprises a silicon basal framework, a socle beam, a mass block, a strain varistor arranged at the fixed end part of the socle beam, the mass block and the silicon basal framework, a reference varistor arranged on the silicon basal framework and a peripheral zero-regulating resistor arranged outside the silicon basal framework; the peripheral zero-regulating resistor, the strain varistors and the reference varistor are connected to form a wheatstone bridge, the peripheral zero-regulating resistor is independently taken as a bridge arm of the wheatstone bridge; and the peripheral zero-regulating resistor is a varistor which is produced on anther silicon substrate with the same property by adopting an ion injection technology, and the wheatstone bridge containing the varistor is zeroed by controlling the ion injection speed when the varistor is produced. The invention has the advantages of convenient zeroing, low temperature drift, small error output and large operation temperature range.

The invention discloses an MEMS piezoresistive accelerometer. The MEMS piezoresistive accelerometer comprises a substrate, a frame, elastic beams, a main mass block, secondary mass blocks, an upper sealing cap and a plurality of sets of piezoresistors, wherein the main mass block is arranged in the center of the frame through the elastic beams in a supporting suspension mode, the frame is fixed to the upper end of the substrate, the secondary mass blocks are arranged on the elastic beams respectively, a specially-shaped elastic beam structure is formed by the secondary mass blocks and the elastic beams, the piezoresistors are arranged in the middle of the elastic beams and the positions of connection between the elastic beams and the frame respectively, the main mass block and the elastic beams are the same in thickness, the upper sealing cap is fixed to the upper end face of the frame, a groove structure is arranged inside the upper sealing cup, and the main mass block is arranged inside a groove in a suspended mode, and can freely move when sensing inertia force in all the directions. According to the MEMS piezoresistive accelerometer, due to the facts that the structure that the elastic beams and the single main mass block are arranged is adopted, and changes of stress, at different positions, of the specially-shaped elastic beams are reflected when the main mass block senses the inertia force in different directions, the size of a device is effectively reduced, and the MEMS piezoresistive accelerometer has the advantages of being high in sensitivity and natural frequency, good in high-overload resistant capacity and the like.

The invention discloses a low cross-axis sensitivity piezoresistive accelerometer structure and a manufacturing method thereof and belongs to the field of micro-electro-mechanical systems. A low cross-axis sensitivity piezoresistive accelerometer is formed by a mass block (1), eight support beams (2), four sensing beams (3) and a frame (4). The center of gravity of the mass block (1) is located ina neutral plane of the support beams (2). The upper surfaces of the sensing beams (3) are located on the surface of a chip such that piezoresistors (5) are made on the surfaces of the sensing beams.The thickness of the sensing beams is far smaller than that of the support beams. Under the action of Z-axis acceleration on the surface of a vertical chip, the mass block (1) moves in a Z-axis direction and drives the sensing beams (3) to move together, the strain of the sensing beams (3) is detected by the piezoresistors (5), thus Z-axis acceleration is obtained. Since the center of gravity of the mass block (1) is located in the neutral plane of the support beams (2), the deflection angle of the mass block (1) under X-axis or Y-axis acceleration within the chip surface is small, and so thestructure has small cross-axis sensitivity.

The invention relates to a microaccelerometer, in particular to an array type single-chip integrated microaccelerometer. The technical problems of large size of the conventional acceleration sensor, incapability of realizing the full scale output of the conventional accelerometer unit, high breakage rate of the root of a clamped beam and incapability of realizing the optimal configuration of a high-low-range accelerator are solved. The array type single-chip integrated microaccelerometer comprises a monocrystalline silicon material structural layer (2), and the structural layer (2) is divided into a left part and a right part. A first piezoresistive accelerometer unit (21) and a second piezoresistive accelerometer unit (22) are integrated on the upper and lower parts of the right part of the structural layer (2) respectively, and have different ranges. A complementary metal oxide semiconductor (CMOS) circuit for amplifying and filtering output signals of the first and second piezoresistive accelerometer units (21 and 22) is integrated on the left part of the structural layer (2). Accelerometer array units and a signal processing circuit are integrated on the same chip, so that the microaccelerometer is miniaturized and integrated.

The invention provides a three-dimensional MEMS (Micro-electromechanical Systems) accelerometer measurement part for petroleum well logging and a preparation method thereof. The three-dimensional MEMS accelerometer measurement part comprises six cube silicon substrates of which the surfaces are all provided with accelerometers; the cube silicon substrates are packaged by insulating materials and are connected with an external circuit by wires; and each accelerometer comprises n*n measurement units which are connected in parallel. A piezoresistive accelerometer on the basis of an MEMS technology can measure three-dimensional dynamic acceleration of a drill bit in the well logging process during drilling, can be adapted to the harsh underground working environment, has a small size and has higher accuracy.

The invention discloses a method of making a self-aligned MEMS piezoresistive accelerometer, comprising the following steps: making a cavity at the bottom of a silicon substrate through a KOH etching process; growing an oxide layer and a silicon nitride layer on the top of the silicon substrate in sequence from bottom to top; making a piezoresistive pattern and a structure release pattern on the silicon nitride layer at the same time through a lithography process, and etching the silicon nitride layer at the piezoresistive pattern and at the structure release pattern; etching the oxide layer at the piezoresistive pattern, and forming a piezoresistor through an injecting process and an annealing process; etching the oxide layer at the structure release pattern to form a structure release area; deeply etching the silicon substrate in the structure release area to form a movable structure, thus getting an MEMS piezoresistive accelerometer. The piezoresistive pattern and the structure release pattern are formed in the same lithography process. There is no need for equipment to carry out alignment in the machining process. Self-alignment of the piezoresistor and a device structure is realized. Thus, the symmetry of devices is improved, error caused by position deviation of the piezoresistor is reduced, and the performance of devices is improved.

The invention discloses a piezoresistive triaxial accelerometer. The piezoresistive triaxial accelerometer comprises a supporting frame, a mass block, and an elastic cantilever beam; the mass block issuspended at the central position of the support frame through the elastic cantilever beam; a plurality of strain piezoresistors with equal resistance values are symmetrically distributed on the elastic cantilever beam between the support frame and the mass block; limiting modules are arranged at the four inner corners of the supporting frame correspondingly. X-direction anti-overload gaps and Y-direction anti-overload gaps are formed between the limiting modules and the adjacent elastic cantilever beams and between the limiting modules and the mass blocks, an upper cover plate and a lower cover plate are arranged on the upper side and the lower side of the supporting frame respectively, and Z-direction anti-overload gaps are formed between the mass blocks and the lower cover plate and between the mass blocks and the upper cover plate. The piezoresistive triaxial accelerometer has higher sensitivity, accuracy and rigidity, facilitates resetting of the mass block, reduces system errors, improves measurement precision and reduces interaxial coupling of the accelerometer.

The invention discloses a piezoresistance-type triaxial accelerometer with high output stability. The accelerometer comprises an SOI substrate, an upper glass cover plate and a lower glass cover plate, and a center quality block is supported on a zigzag frame through eight rectangular beams. A phosphorus element is poured into the periphery of each piezoresistor on the corresponding beam through icons, heavy doping is conducted, electric potential which is higher than or equal to the power supply voltage of the wheatstone bridge is accessed to the periphery of each piezoresistor through a welding disk, the electric leakage phenomenon of a piezoresistor strip is avoided, and the output stability of the piezoresistance-type accelerometer is achieved.

The invention discloses a silicon piezoresistive type accelerometer carrying out detection based on the Josephson effect. The silicon piezoresistive type accelerometer carrying out detection based on the Josephson effect comprises a bonding substrate, a supporting frame body, a Josephson device, an elastic beam, a mass block and a piezoresistor. The silicon piezoresistive type accelerometer carrying out detection based on the Josephson effect has the advantages of being capable of converting acceleration signals into strictly consistently compensated current step signals by integrating the Josephson device and a silicon piezoresistive device, reasonable in structure and high in sensitivity, adopting digitized output, and being simple in detection circuit, convenient to use, good in reliability and suitable for microminiaturization, and can effectively solve the problems of low sensitivity, low effective resolution ratio, high threshold detection lower limit and the like of a high overload type sensor.

The invention discloses an out-of-plane piezoresistive accelerometer chip with pure axial deformation sensitive beams and a preparation method of the out-of-plane piezoresistive accelerometer chip, the chip comprises two symmetrically arranged mass blocks, the outer end faces of the two mass blocks are respectively connected with a chip outer frame, and the inner end faces of the two mass blocks are connected through two groups of sensitive beams; the four sensitive beams form a Wheatstone full-bridge circuit; the mass blocks are used for directly sensing surface applied speed signals, when the chip is subjected to acceleration in the Z direction, the two mass blocks synchronously move, the two mass blocks and the sensitive beam fixed to the two mass blocks also keep synchronous movement,and therefore pure axial deformation of the sensitive beam is met.