32 results about "Piezoresistive accelerometer" patented technology

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 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.

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 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.

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.

The invention discloses a piezoresistive type high overload microelectromechanical system (MEMS) accelerometer. The piezoresistive type high overload MEMS accelerometer comprises a frame, a group of main beams, a group of micro beams and a mass block. The main beams are arranged in the frame and connected with the mass block. The micro beams are respectively arranged on one or two sides of the main beams and parallel to the same. When the micro beams are respectively arranged on one side of the main beams, the whole accelerometer is of a centrosymmetric structure. When the micro beams are respectively arranged on two sides of the main beams, the whole accelerometer is of a full symmetric structure. As structures of the main beams and the micro beams are simply combined with one silicon wafer, a contradiction of a negative correlation between a high range and a high sensitivity is overcome, and the technology is simplified to achieve production in a large scale; meanwhile, stress concentration in corners caused by direct connection between the beams and the mass block is eliminated through buffer locks, and accordingly the accelerometer is less prone to damage.

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 silicon piezoresistive accelerometer based on Josephson effect detection, which comprises: a bonding substrate, a supporting frame, a Josephson device, an elastic beam, a quality block and a piezoresistor. The beneficial effect of the present invention is that the Josephson device is integrated with the silicon piezoresistor, the acceleration signal can be converted into a current step signal that compensates strictly and consistently, the structure is reasonable, the sensitivity is high, the digital output is simple, the detection circuit is simple, the use is convenient, and the reliability is good. Suitable for miniaturization. It can effectively solve the problems of low sensitivity, low effective resolution, and high detection threshold lower limit in high overload sensors.

The invention discloses a pure axial deformation based MEMS three-axis piezoresistive accelerometer chip and a preparation method thereof. An X measurement unit, a Y measurement unit and a Z measurement unit in a sensor are used for measuring the accelerations in the X direction, the Y direction and the Z direction respectively, so that the separate measurement of the accelerations in the three directions is realized; each measurement unit comprises mass blocks, a supporting beam and a sensitive beam; for no matter which of the measurement units, the supporting beam and the sensitive beam areseparately arranged through the mass blocks, the supporting beam supports the mass blocks to move, and the stress is mainly concentrated in the sensitive beam, so that the resistance value of a piezoresistor strip on the sensitive beam is changed; the supporting beam and the sensitive beam perform respective functions, so that the direct coupling relation between the sensitivity and the resonant frequency is greatly weakened; meanwhile, due to the synchronous movement of the two mass blocks, the two ends of the sensitive beam fixed with the mass blocks synchronously move, and the sensitive beam always meets the pure axial deformation condition; and under the same resonant frequency, the sensitivity of the sensor is optimal, so that the sensor chip has good performance indexes.

Disclosed is a piezoresistive acceleration sensor having a full-bridge microbeam structure, comprising a frame (1), a cantilever beam (2), microbeams (3) and a mass block (4). The cantilever beam (2) is on the axis of symmetry of the mass block (4), the microbeams (3) are four in number, and are axisymmetrically distributed on an edge of the mass block (4) using the axis on which the cantilever beam (2) is located, and piezoresistive sensing resistors are provided on the four microbeams, the four piezoresistive sensing resistors constituting a Wheatstone full bridge circuit. Amplifying the strain of the cantilever beam increases the sensitivity; the four piezoresistive sensing resistors are all within a chip, and because the effects of resistance drift on the circuit caused by measuring changes in the ambient temperature cancel each other out in a full bridge circuit, the temperature stability is increased; and the four microbeams increase the restriction on the vibration of the mass block, raising the first order resonance frequency.

The invention provides a piezoresistive acceleration and pressure integrated sensor based on anodic bonding and packaging and a method for manufacturing the piezoresistive acceleration and pressure integrated sensor. The piezoresistive acceleration and pressure integrated sensor integrates a piezoresistive acceleration sensor and a piezoresistive pressure sensor and is provided with a first bonding glass-silicon substrate-second bonding glass type sandwich structure. The piezoresistive acceleration and pressure integrated sensor is novel in structure, low in weight, small in size, high in stability, and high in anti-pollution capacity. In addition, according to the piezoresistive acceleration and pressure integrated sensor and the method for manufacturing the piezoresistive acceleration and pressure integrated sensor, the same technology is applied to the same chip, the pressure measurement capacity and the acceleration measurement capacity are achieved through different kinds of design, and the technological processes are simple and easy to implement. The piezoresistive acceleration and pressure integrated sensor has a certain application prospect in the fields such as the aviation field, the military field, the automobile field and the environment monitoring field.

The invention provides a measuring component of a three-dimensional MEMS accelerometer for petroleum well logging and a preparation method thereof, which includes a cube silicon base with accelerometers on six surfaces, the cube silicon base is encapsulated by a heat-insulating material, and Connect to external circuits by wires. The accelerometer includes n×n measuring units connected in parallel. This piezoresistive accelerometer based on MEMS technology can measure the three-dimensional dynamic acceleration of the drill bit during logging while drilling, and can adapt to the harsh working environment downhole. It is small in size and has higher accuracy.