2608results about How to "Lower on-resistance" patented technology

Various embodiments for improved power devices as well as their methods of manufacture, packaging and circuitry incorporating the same for use in a wide variety of power electronic applications are disclosed. One aspect of the invention combines a number of charge balancing techniques and other techniques for reducing parasitic capacitance to arrive at different embodiments for power devices with improved voltage performance, higher switching speed, and lower on-resistance. Another aspect of the invention provides improved termination structures for low, medium and high voltage devices. Improved methods of fabrication for power devices are provided according to other aspects of the invention. Improvements to specific processing steps, such as formation of trenches, formation of dielectric layers inside trenches, formation of mesa structures and processes for reducing substrate thickness, among others, are presented. According to another aspect of the invention, charge balanced power devices incorporate temperature and current sensing elements such as diodes on the same die. Other aspects of the invention improve equivalent series resistance (ESR) for power devices, incorporate additional circuitry on the same chip as the power device and provide improvements to the packaging of charge balanced power devices.

A silicon carbide semiconductor device capable of achieving a decrease in ON resistance and an increase in breakdown voltage and a method for manufacturing a silicon carbide semiconductor device. A silicon carbide semiconductor device includes a silicon carbide substrate and a drift layer. The drift layer includes a breakdown voltage holding layer extending from a point where a doping concentration has a predetermined value to a surface of the drift layer. The doping concentration in the breakdown voltage holding layer continuously decreases from the point where the doping concentration has the predetermined value to a modulation point located further toward the surface of the drift layer than a midpoint in a film thickness direction of the breakdown voltage holding layer. The doping concentration in the breakdown voltage holding layer continuously increases from the modulation point to the surface of the drift layer.

Various embodiments for improved power devices as well as their methods of manufacture, packaging and circuitry incorporating the same for use in a wide variety of power electronic applications are disclosed. One aspect of the invention combines a number of charge balancing techniques and other techniques for reducing parasitic capacitance to arrive at different embodiments for power devices with improved voltage performance, higher switching speed, and lower on-resistance. Another aspect of the invention provides improved termination structures for low, medium and high voltage devices. Improved methods of fabrication for power devices are provided according to other aspects of the invention. Improvements to specific processing steps, such as formation of trenches, formation of dielectric layers inside trenches, formation of mesa structures and processes for reducing substrate thickness, among others, are presented. According to another aspect of the invention, charge balanced power devices incorporate temperature and current sensing elements such as diodes on the same die. Other aspects of the invention improve equivalent series resistance (ESR) for power devices, incorporate additional circuitry on the same chip as the power device and provide improvements to the packaging of charge balanced power devices.

A MESFET based boost converter includes an N-channel MESFET connected to a node Vx. An inductor connects the node Vx to a battery or other power source. The node Vx is also connected to an output node via a Schottky diode or a second MESFET or both. A control circuit drives the MESFET (and the second MESFET) so that the inductor is alternately connected to ground and to the output node. The maximum voltage impressed across the low side MESFET is optionally clamped by a Zener diode. In some implementations, the MESFET is connected in series with a MOSFET. The MOSFET is switched off during sleep or standby modes to minimize leakage current through the MESFET. The MOSFET is therefore switched at a low frequency compared to the MESFET and does not contribute significantly to switching losses in the converter. In other implementations, more than one MESFET is connected in series with a MOSFET, the MOSFETs being switched off during periods of inactivity to suppress leakage currents.

Various embodiments for improved power devices as well as their methods of manufacture, packaging and circuitry incorporating the same for use in a wide variety of power electronic applications are disclosed. One aspect of the invention combines a number of charge balancing techniques and other techniques for reducing parasitic capacitance to arrive at different embodiments for power devices with improved voltage performance, higher switching speed, and lower on-resistance. Another aspect of the invention provides improved termination structures for low, medium and high voltage devices. Improved methods of fabrication for power devices are provided according to other aspects of the invention. Improvements to specific processing steps, such as formation of trenches, formation of dielectric layers inside trenches, formation of mesa structures and processes for reducing substrate thickness, among others, are presented. According to another aspect of the invention, charge balanced power devices incorporate temperature and current sensing elements such as diodes on the same die. Other aspects of the invention improve equivalent series resistance (ESR) for power devices, incorporate additional circuitry on the same chip as the power device and provide improvements to the packaging of charge balanced power devices.

The vertical trench MOSFET comprises: an N type epitaxial region formed on an upper surface of an N+ type substrate having a drain electrode on a lower surface thereof; a gate trench extending from a front surface into the N type epitaxial region; a gate electrode positioned in the gate trench so as to interpose an insulator; a channel region formed on the N type epitaxial region; a source region formed on the channel region; a source electrode formed on the source region; a source trench extending from the front surface into the N type epitaxial region; and a trench-buried source electrode positioned in the source trench so as to interpose an insulator, wherein the source electrode contacts with the trench-buried source electrode.

A power semiconductor device includes a plurality of trenches formed within a semiconductor body, each trench including one or more electrodes formed therein. In particular, according to embodiments of the invention, the plurality of trenches of a semiconductor device may include one or more gate electrodes, may include one or more gate electrodes or one or more source electrodes, or may include a combination of both gate and source electrodes formed therein. The trenches and electrodes may have varying depths within the semiconductor body.

A nitride semiconductor device includes: a first nitride semiconductor layer formed of non-doped AlxGa1-XN (0≦X<1); a second nitride semiconductor layer formed on the first nitride semiconductor layer of non-doped or n-type AlYGa1-YN (0<Y≦1, X<Y), and having a smaller lattice constant than that of the first nitride semiconductor layer; a third nitride semiconductor layer formed on the second nitride semiconductor layer of a non-doped or n-type nitride semiconductor, and having a lattice constant equal to that of the first nitride semiconductor layer; a fourth nitride semiconductor layer formed on the third nitride semiconductor layer of InWAlZGa1-W-ZN (0<W≦1, 0<Z<1); a gate electrode formed in a recess structure having a bottom face which arrives at the third nitride semiconductor layer; and a source electrode and a drain electrode.

An enhancement mode High Electron Mobility Transistor (HEMT) comprising a p-type nitride layer between the gate and a channel of the HEMT, for reducing an electron population under the gate. The HEMT may also comprise an Aluminum Nitride (AlN) layer between an AlGaN layer and buffer layer of the HEMT to reduce an on resistance of a channel.

The present invention provides a silicon carbide substrate, an epitaxial layer provided substrate, a semiconductor device, and a method for manufacturing the silicon carbide substrate, each of which achieves reduced on-resistance. The silicon carbide substrate is a silicon carbide substrate having a main surface, and includes: a SiC single-crystal substrate formed in at least a portion of the main surface; and a base member disposed to surround the SiC single-crystal substrate. The base member includes a boundary region and a base region. The boundary region is adjacent to the SiC single-crystal substrate in a direction along the main surface, and has a crystal grain boundary therein. The base region is adjacent to the SiC single-crystal substrate in a direction perpendicular to the main surface, and has an impurity concentration higher than that of the SiC single-crystal substrate.

A stereo class-D audio system includes a first die including four monolithically integrated NMOS high-side devices and a second a second die including four monolithically integrated PMOS low-side devices. The audio system also includes a set of electrical contacts for connecting the high and low-side devices to components within the a stereo class-D audio system, the set of electrical contacts including at least one supply contact for connecting the drains of the high-side devices to a supply voltage (Vcc) and at least one ground contact for connecting the drains of the low-side devices to ground, the electrical contacts also including respective contacts for each source of the high and low-side devices allowing the source of each high-side device to be connected to the source of a respective low-side device to form two H-bridge circuits.

A trench MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) with a trench termination, including a substrate including a drain region which is strongly doped and a doping epi layer region, which is weekly doped the same type as the drain region, on the drain region; a plurality of source and body regions formed in the epi layer; a metal layer including a plurality of metal layer regions which are connected to respective source and body, and gate regions forming metal connections of the MOSFET; a plurality of metal contact plugs connected to respective metal layer regions; a plurality of gate trenches filled with polysilicon to form a plurality of trenched gates on top of epi layer; an insulating layer deposited on the epi layer formed underneath the metal layer with a plurality of metal contact holes therein for contacting respective source and body regions; a margin terminating gate trench which is around the gate trenches; and a margin terminating active region which is formed underneath the margin terminating gate trench.

A method for forming thick oxide at the bottom of a trench formed in a semiconductor substrate includes forming a conformal oxide film that fills the trench and covers a top surface of the substrate. and etching the oxide film off the top surface of the substrate and inside the trench to leave a substantially flat layer of oxide having a target thickness at the bottom of the trench. The oxide film can be deposited by sub-atmospheric chemical vapor deposition processes, directional Tetraethoxysilate (TEOS) processes, or high density plasma deposition processes that form a thicker oxide at the bottom of the trench than on the sidewalls of the trench.

The on-resistance of a semiconductor device having a power transistor with a trench gate structure is reduced. A power MIS-FET with a trench gate structure is so formed that the relation expressed as 0≦b≦a holds, where a is the distance between an end of an interlayer insulating layer over the upper face of a semiconductor region for source and the end (position on the periphery of a trench) of the upper face of the semiconductor region for source farther from the gate electrode; and b is the length of the overlap between the interlayer insulating layer and the upper face of the semiconductor region for source. (b is the distance between the position of the end of the interlayer insulating layer over the upper face of the semiconductor region for source and position on the periphery of a trench). As a result, the area of contact between source pads and the semiconductor regions for source is increased, and further the distance between the source pads and a channel forming region can be shortened. Therefore, the on-resistance of the power MIS-FET with a trench gate structure can be reduced.

A power transistor having of a plurality of vertical MOSFET devices combined in parallel to achieve high-performance operation and methods of fabricating this device.

A series of gate drive circuits for MESFETs are provided. The gate drive circuits are intended to be used in switching regulators where at least one switching device is an N-channel MESFET. For regulators of this type, the gate drive circuits provide gate drive at the correct voltage to ensure that MESFETs are neither under driven (resulting in incorrect circuit operation) nor over driven (resulting in MESFET damage or excess current or power loss).

A DC-DC converter has converter circuit portions 11 and 12, transformers Tr.sub.1 and T r.sub.2, and rectifier circuit portions 21 and 22. Two sets of converter circuit portions 11 and 12 respectively include two pairs of switching elements Q.sub.1 to Q.sub.4, and two pairs of switching elements Q.sub.5 to Q.sub.8 connected in full bridge configuration, series capacitors C.sub.1 and C.sub.2 are inserted and connected between the converter circuit portions 11 and 12 and the transformers Tr.sub.1 and Tr.sub.2 respectively. The switching phase of one switching element Q.sub.4 or Q.sub.8 is shifted by a 1 / 3n period from the switching phase of the other switching element Q.sub.1 or Q.sub.5 in the pair of switching elements. The switching phases of corresponding switching elements Q.sub.1 and Q.sub.5 in the converter circuit portions 11 and 12 are shifted by a 1 / 2n period from each other.

In a semiconductor device in which a diode and a high electron mobility transistor are incorporated in the same semiconductor chip, a compound semiconductor layer of the high electron mobility transistor is formed on a main surface (first main surface) of a semiconductor substrate of the diode, and an anode electrode of the diode is electrically connected to an anode region via a conductive material embedded in a via hole (hole) reaching a p+ region which is the anode region of the main surface of the semiconductor substrate from a main surface of the compound semiconductor layer.

A semiconductor 100 has a P− body region and an N− drift region in the order from an upper surface side thereof. A gate trench and a terminal trench passing through the P− body region are formed. The respective trenches are surrounded with P diffusion regions at the bottom thereof. The gate trench builds a gate electrode therein. A P−− diffusion region, which is in contact with the end portion in a lengthwise direction of the gate trench and is lower in concentration than the P− body region and the P diffusion region, is formed. The P−− diffusion region is depleted prior to the P diffusion region when the gate voltage is off. The P−− diffusion region serves as a hole supply path to the P diffusion region when the gate voltage is on.

A lateral double-diffused MOS (LDMOS) transistor is provided. The LDMOS transistor includes a semiconductor substrate 202 formed of a material having p-conductivity type impurities, a drift region formed of a material having n-conductivity type impurities on the semiconductor substrate, a first buried layer 206 of p-type material and a second buried layer 208 formed of n-type material. Layers 206 and 208 are arranged at the boundary between the semiconductor substrate and the drift region. A first well region 210 of p-type material contacts the first buried layer 206 n-type in a first portion 1 of the drift region. A first source region 214 conductivity in a predetermined upper region of the first well region, a drain region formed of a material having second conductivity type impurities in a predetermined region of the drift region, the drain region being spaced a predetermined gap apart from the first well region, a third buried layer formed of a material having first conductivity type impurities in a second region of the drift region, the third buried layer being overlapped with a part of an upper portion of the first buried layer, a second well region formed of a material having first conductivity type impurities in the second region of the drift region, the second well region being overlapped with the third buried layer, a second source region formed of a material having second conductivity type impurities in a predetermined upper region of the second well region, a gate insulating layer formed in a first channel region inside the first well region and in a second channel region inside the second well region, a gate electrode formed on the gate insulating layer, a source electrode formed to be electrically connected to the first source region and the second source region, and a drain electrode formed to be electrically connected to the drain region.

A MESFET based buck converter includes an N-channel MESFET between a battery or other power source and a node Vx. The node Vx is connected to an output node via an inductor and to ground via a Schottky diode or a second MESFET or both. A control circuit drives the MESFET (and the second MESFET) so that the inductor is alternately connected to the battery and to ground. The maximum voltage impressed across the high side MESFET is optionally clamped by a Zener diode. In some implementations, the MESFET is connected in series with a MOSFET. The MOSFET is switched off during sleep or standby modes to minimize leakage current through the MESFET. The MOSFET is therefore switched at a low frequency compared to the MESFET and does not contribute significantly to switching losses in the converter. In other implementations, more than one MESFET is connected in series with a MOSFET the MOSFETs being switched off during periods of inactivity to suppress leakage currents.

A trench MOSFET with split gates and diffused drift region for on-resistance reduction is disclosed. Each of the split gates is symmetrically disposed in the middle of the source electrode and adjacent trench sidewall of a deep trench. The inventive structure can save a mask for definition of the location of the split gate electrodes. Furthermore, the fabrication method can be implemented more reliably with lower cost.

The invention discloses a half-bridge LLC resonant converter with a synchronous rectification function that includes a first switch; a second switch; a first transformer; a first synchronous rectifier; a second synchronous rectifier; a controller; and a second transformer. The controller of the half-bridge LLC resonant converter with a synchronous rectification function can control the first synchronous rectifier and the second synchronous rectifier directly and the connected second transformer also can control the first switch and the second switch directly. The first synchronous rectifier and second synchronous rectifier having a low conducting resistance substitute the rectifier and greatly lower the power consumption. The controller outputs a control signal to drive a transformer to output a signal to the primary winding, and its signal delay is formed by a delay of an electronic circuit and a power MOS switch of the first switch and second switch.

In an insulation type AC-dc converter in which input current from a commercial power supply is converted to obtain insulated direct current, the overall efficiency is raised and the structure is simplified. A multi-resonance type half-bridge DC-DC converter having an insulation transformer T is used as a first converter, and a boosting chopper circuit for power factor improvement is used as a second converter. Hence through multi-resonance operation, increases in losses can be suppressed even when the switching frequency is raised, and because a half-bridge circuit is used, switching elements and similar with lower voltage ratings can be employed, whereby overall efficiency can be increased. Moreover, a voltage substantially similar to the full-wave rectified waveform of the power supply voltage is obtained from the output capacitor at the boosting chopper circuit input, whereby there is no need for a feed-forward circuit across the insulation transformer, and moreover the electrolytic capacitor which had to be provided on the converter input side is unnecessary. This is advantageous for achieving miniaturization and a thin design.