68results about How to "Raise the eigenfrequency" patented technology

The invention relates to a SiGe bipolar complementary metal oxide semiconductor (BiCMOS) radio-frequency power amplifier. The amplifier comprises a first-stage pre-amplification transistor, a second-stage power amplification transistor, a first-stage biasing circuit, a second-stage biasing circuit, an input matching network and an impedance conversion network. The circuit structure of the invention consists of a first-stage pre-amplification circuit and a second-stage power amplification circuit which are connected with each other through a coupling capacitor. The first-stage pre-amplification transistor is a standard SiGe transistor, and the linearity of the circuit is enhanced by a remote control (RC) serial feedback circuit; and the second-stage power amplification transistor is a high-voltage SiGe transistor and can reach relatively high output power. Both the first biasing circuit and the second biasing circuit have bipolar transistor current mirror structures, and temperature stability is enhanced by temperature negative feedback technology. The amplifier has high linearity and relatively high output power.

The invention belongs to the technical field of semiconductor photoelectrons, and relates to a base-region-gradient uni-traveling-carrier double-heterojunction phototransistor (UTC-DHPT) detector capable of realizing high responsivity and high cut-off frequency. The detector comprises an InP substrate, an emitting electrode, a base electrode and a collector electrode; an InP buffer layer, an InGaAsP secondary collector region, an InGaAsP collector region, two InGaAsP transition layers different in material band gap wavelength, an InGaAsP base region gradient in material band gap wavelength, an InP emitting region, an InP cover layer and an InGaAs Ohmic contact layer are prepared on the InP substrate in sequence by the aid of a metal-organic chemical vapor deposition (MOCVD) method; the emitting electrode is produced on the InGaAs Ohmic contact layer by a sputtering method; the base electrode is produced on the InGaAsP base region through the sputtering method; the collector electrode is produced on the InP substrate through a vapor deposition method.

The invention belongs to the technical field of semiconductor devices, and particularly relates to a field-induced tunneling enhanced HEMT (high electron mobility transistor) device. The field-induced tunneling enhanced HEMT device is different from conventional AlGaN/GaN HEMT devices in that metal sources are in Schottky barrier contact instead of ohm contact in conventional structures; and metal gates are not positioned between the sources and drains but form insulating gate electrodes at the edges, away from the drains, of the sources through etching grooves. Field-control conductive channels are realized by means of the insulating layer and groove technology, field control of the field-control conductive channels is realized by voltage applied to the groove gate electrodes, and electrons subjected to band bending can directly tunnel barriers to be accumulated below the channels in gate modulation when forward voltage is applied to the gate electrodes, so that normally closed channels are realized, and frequency characteristics of the device can be promoted without affecting reverse voltage withstand capability of the device. Meanwhile, the preparation process of the device is compatible to traditional processes, and thereby solid foundation is established for the GaN power integration technology.

A lithographic apparatus includes a support constructed to support a patterning device, the patterning device being capable of imparting a radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate on a central area; and a projection system configured to project the patterned radiation beam onto a target portion of the substrate in a first direction. The apparatus further includes a positioning device to position the substrate table, wherein the positioning device includes a plurality of actuators arranged to, in use, exert forces to position the substrate table, the forces substantially being directed in a plane substantially perpendicular to the first direction and wherein the plurality of actuators are arranged outside a central volume of the substrate table, the central volume being obtained by projecting the central area along the first direction.

The invention discloses a full-difference E-type power amplifier. The amplifier is a circuit composed of a Bipolar device, a CMOS device and a passive device, wherein a difference input pair is the Bipolar device; a cross coupling pair is an NMOS tube; the amplifier adopts a two-stage structure, the first pre-amplifying stage performs a pretreatment for an input constant envelope signal so as to meet the requirement for fast opening and closing of the second power amplifying stage; and the cross coupling pair structure is added into each stage so as to accelerate the on/off speed, satisfy high frequency application and reduce the width length ratio of a main switching pipe. Meanwhile, the difference input also avoids the influence of a second harmonic wave on a substrate, completely filters and removes secondary and high and even order harmonic waves and eliminates the substrate coupling such that the device is not easy to puncture. The invention has the following advantages of high power efficiency, low harmonic distortion, low power voltage, simple structure, fast working speed and low power consumption and the like.

A timing cover for an engine includes a plurality of dome-shaped embossed portions formed at positions of the timing cover that are most susceptible to vibration, based on an analysis of vibration modes of the timing cover.

The invention belongs to microelectronic technology and in particular to a tunable film bulk acoustic resonator (FBAR) comprising a substrate, a cavity, a bottom electrode layer, a tuning layer and apiezoelectric oscillation stack. The piezoelectric oscillation stack comprises an intermediate electrode layer, a piezoelectric layer, and a top electrode layer. A DC bias voltage is applied to the intermediate electrode layer and the bottom electrode layer. The FBAR DC bias voltage is applied to the bottom electrode and the intermediate electrode, the tuning layer has a piezoelectric characteristic, and the bottom electrode layer is in an annular shape. Thus, under a low DC bias voltage, the FBAR can produce a large offset displacement, resulting in a large change in characteristic frequency.Therefore, the large resonance frequency adjustment of the FBAR can be realized at a low voltage, thereby greatly expanding the application range of the FBAR.

The invention relates to a two-wire system built-in charge amplifying circuit based on a field-effect tube and belongs to the technical field of low-noise two-wire system charge-voltage conversion amplifying circuit and structure design. According to the invention, at an input stage, the change in a small-signal voltage-controlled current of a field-effect tube is adopted for realizing the impedance conversion from a high internal resistance alternating charge signal to a low internal voltage signal; a biasing circuit is formed by resistance differential pressure; a signal passes by a common base current follower formed by a PNP bipolar transistor and a common emitter output circuit formed by a NPN bipolar transistor and then is compounded with a power supply, so that the two-wire system signal transmission can be formed; an input end filtering capacitor can realize the reduction of noise interference; and a signal voltage is compounded and overlapped with a direct current bias voltage. The field-effect tube is low in noise and the field-effect tube and the bipolar transistor are high in characteristic frequency, so that the circuit frequency response range is wide, and the output driving capacity is higher; few electron components are used, and the resistance elements are subjected to resistance slurry sintering and laser resistor trimming and are easy to integrate and control precision; and a circuit base plate is made from aluminum oxide ceramics, so that the structure strength is high.

The invention discloses a heterojunction bipolar transistor, and particularly relates to an ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor. According to the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor, a stepped distribution structure that the number of base region Ge components gradually increases from an emitter junction side to a collector junction side is adopted, current gain of a device slows down along with the trend of temperature changes, and drifting of a quiescent operating point of the device can be prevented in a wide temperature area; meanwhile, the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor can improve the characteristic frequency of the device and sensitivity of changes, along with the temperature, of the device. In addition, due to the fact that the non-equal finger separation distance symmetrical structure that indexes of the finger separation distances of emitter electrode fingers increase from the two sides of the device to the center of the device is further adopted by the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor, the phenomenon that heat of emitter electrode fingers on the outer side flows into the center can be effectively prevented from happening, the purpose of reducing thermal coupling effect among emitter electrode fingers and the purpose of improving uniformity of distribution of the temperature of an active area of the device are achieved, and the purpose of improving the thermal stability of the ultra-wide temperature area high-thermal-stability microwave power SiGe heterojunction bipolar transistor is achieved.

The invention discloses a GaAs based composite collecting region trajectory transmitting heterojunction bipolar transistor comprising, a semi-insulating GaAs substrate, a N#+[+] adulterated GaAs collecting sub-region grown on the semi-insulating GaAs substrate, a composite collecting region grown on the N#+[+] adulterated GaAs collecting sub-region, a heavy type P GaAs base grown on the composite collecting region. On the base region a type N InGaP emitting region is formed the top of which is a cap layer used for making Ohm contact, an emitting electrode is formed on the cap layer, and a base electrode is formed on the type N InGaP emitting region on the base region.

The invention discloses a transverse SiGe heterojunction bipolar transistor with adjustable doping concentration. The transverse SiGe heterojunction bipolar transistor is an NPN type or PNP type transverse SiGe HBT (Heterojunction Bipolar Transistor). By applying a positive voltage to a substrate electrode below an emitter region and a base region of an NPN type device (or applying a negative voltage to a substrate electrode below an emitter region and a base region of a PNP type device), the doping concentration of the emitter region can be increased, the doping concentration of the base region can be reduced, and meanwhile, the current gain and the characteristic frequency can be improved. By applying a negative voltage to a substrate electrode below a collector region of the NPN type device (or applying a positive voltage to a substrate electrode below a collector region of the PNP type device), the doping concentration of the collector region can be reduced, and the breakdown voltage can be improved. Compared with a conventional transverse SiGe HBT, the doping concentrations of the three regions can be independently adjusted by changing the external voltages applied to the substrate electrodes below the emitter region, the base region and the collector region, so that the characteristic frequency, the current gain and the breakdown voltage are synchronously improved.

The invention discloses a linear actuator, a hydraulic bearing, and a motor vehicle with such a hydraulic bearing or linear actuator. The invention relates to an electromagnetic linear actuator (16) with a stator (18) and an armature (20) which can be moved relative to the stator (18). The stator (18) has at least one permanent magnet (22) and at least one coil (24), the stator (18) has a conductive element (26) made of a ferromagnetic material, the conductive element (26) extends over the at least one permanent magnet (22) and/or the at least one coil (26), and the armature (18) forms a yoke (34) made of a ferromagnetic material in the longitudinal direction L for the conductive element (26). The invention further relates to a hydraulic bearing (2) with a support spring (36), a working chamber (4), which is filled with a hydraulic fluid, a compensating chamber (6), a partition (8) which is arranged between the working chamber (4) and the compensating chamber (6), a throttle channel (10) which is formed between the working chamber (4) and the compensating chamber (6) for exchanging hydraulic fluid, and a control membrane (12) which is paired with the partition (8) and which is designed to change a working chamber volume (14) of the working chamber (4). The hydraulic bearing (2) has an electromagnetic linear actuator (16) according to the invention, and the armature (20) is mechanically connected to the control membrane (12). The invention additionally relates to a motor vehicle with such a hydraulic bearing (2).

The present invention discloses an electrode lead-out structure in a STI (Shallow Trench Isolation) process, wherein an active region is isolated by a shallow trench, a buried layer is formed at the bottom of the shallow trench, the buried layer enters into the active region and connects with a doped area 1 where the electrode is needed to be led out in the active region, and a deep-groove contact hole is manufactured in an oxide layer of the shallow trench to connect with the buried layer so as to lead the electrode out of the doped area 1. The electrode lead-out structure in the present invention can reduce area of the device, reduce resistance and parasitic capacitance of the led-out electrode, and improve characteristic frequency of the device.