Abstract: N-channel power semiconductor devices in which an insulated field plate is coupled to the drift region, and immobile electrostatic charge is also present at the interface between the drift region and the insulation around the field plate. The electrostatic charge permits OFF-state voltage drop to occur near the source region, in addition to the voltage drop which occurs near the drain region (due to the presence of the field plate).

Abstract: Power semiconductor devices, and related methods, where majority carrier flow is divided into paralleled flows through two drift regions of opposite conductivity types.

Abstract: Various improvements in vertical transistors, such as IGBTs, are disclosed. The improvements include forming periodic highly-doped p-type emitter dots in the top surface region of a growth substrate, followed by growing the various transistor layers, followed by grounding down the bottom surface of the substrate, followed by a wet etch of the bottom surface to expose the heavily doped p+ layer. A metal contact is then formed over the p+ layer. In another improvement, edge termination structures utilize p-dopants implanted in trenches to create deep p-regions for shaping the electric field, and shallow p-regions between the trenches for rapidly removing holes after turn-off. In another improvement, a dual buffer layer using an n-layer and distributed n+ regions improves breakdown voltage and saturation voltage. In another improvement, p-zones of different concentrations in a termination structure are formed by varying pitches of trenches. In another improvement, beveled saw streets increase breakdown voltage.

Abstract: Various improvements in vertical transistors, such as IGBTs, are disclosed. The improvements include forming periodic highly-doped p-type emitter dots in the top surface region of a growth substrate, followed by growing the various transistor layers, followed by grounding down the bottom surface of the substrate, followed by a wet etch of the bottom surface to expose the heavily doped p+ layer. A metal contact is then formed over the p+ layer. In another improvement, edge termination structures utilize p-dopants implanted in trenches to create deep p-regions for shaping the electric field, and shallow p-regions between the trenches for rapidly removing holes after turn-off. In another improvement, a dual buffer layer using an n-layer and distributed n+ regions improves breakdown voltage and saturation voltage. In another improvement, p-zones of different concentrations in a termination structure are formed by varying pitches of trenches. In another improvement, beveled saw streets increase breakdown voltage.

Abstract: In one embodiment, a power MOSFET cell includes an N+ silicon substrate having a drain electrode. An N-type drift layer is grown over the substrate. An N-type layer, having a higher dopant concentration than the drift region, is then formed along with a trench having sidewalls. A P-well is formed in the N-type layer, and an N+ source region is formed in the P-well. A gate is formed over the P-well's lateral channel and has a vertical extension into the trench. A positive gate voltage inverts the lateral channel and increases the vertical conduction along the sidewalls to reduce on-resistance. A vertical shield field plate is also located next to the sidewalls and may be connected to the gate. The field plate laterally depletes the N-type layer when the device is off to increase the breakdown voltage. A buried layer and sinker enable the use of a topside drain electrode.

Abstract: A semiconductor device includes a semiconductor layer of a first conductivity type and a semiconductor layer of a second conductivity type formed thereon. The semiconductor device also includes a body layer extending a first predetermined distance into the semiconductor layer of the second conductivity type and a pair of trenches extending a second predetermined distance into the semiconductor layer of the second conductivity type. Each of the pair of trenches consists essentially of a dielectric material disposed therein and a concentration of doping impurities present in the semiconductor layer of the second conductivity type and a distance between the pair of trenches define an electrical characteristic of the semiconductor device. The semiconductor device further includes a control gate coupled to the semiconductor layer of the second conductivity type and a source region coupled to the semiconductor layer of the second conductivity type.

Abstract: A semiconductor device according to the present invention includes a semiconductor layer having a trench, a first insulating film formed along an inner surface of the trench, and an upper electrode and a lower electrode embedded in the trench via the first insulating film and disposed above and below a second insulating film. An electric field relaxation portion that relaxes an electric field arising between the upper electrode and the semiconductor layer is provided between a side surface of the trench and a lower end portion of the upper electrode.

Abstract: Lateral power devices where immobile electrostatic charge is emplaced in dielectric material adjoining the drift region. A shield gate is interposed between the gate electrode and the drain, to reduce the Miller charge. In some embodiments the gate electrode is a trench gate, and in such cases the shield electrode too is preferably vertically extended.

Abstract: N-channel power semiconductor devices in which an insulated field plate is coupled to the drift region, and immobile electrostatic charge is also present at the interface between the drift region and the insulation around the field plate. The electrostatic charge permits OFF-state voltage drop to occur near the source region, in addition to the voltage drop which occurs near the drain region (due to the presence of the field plate).

Abstract: A power MOSFET cell includes an N+ silicon substrate having a drain electrode. A low dopant concentration N-type drift layer is grown over the substrate. An N-type layer, having a higher dopant concentration than the drift region, is then formed and etched to have sidewalls. A P-well is formed in the N-type layer, and an N+ source region is formed in the P-well. A gate is formed over the P-well's lateral channel and has a vertical extension next to the top portion of the sidewalls. A positive gate voltage inverts the lateral channel and increases the conduction along the sidewalls to reduce on-resistance. A vertical shield field plate is also located next to the sidewalls and extends virtually the entire length of the sidewalls. The field plate laterally depletes the N-type layer when the device is off to increase the breakdown voltage.

Abstract: N-channel power semiconductor devices in which an insulated field plate is coupled to the drift region, and immobile electrostatic charge is also present at the interface between the drift region and the insulation around the field plate. The electrostatic charge permits OFF-state voltage drop to occur near the source region, in addition to the voltage drop which occurs near the drain region (due to the presence of the field plate).

Abstract: A lateral device includes a gate region connected to a drain region by a drift layer. An insulation region adjoins the drift layer between the gate region and the drain region. Permanent charges are embedded in the insulation region, sufficient to cause inversion in the insulation region.

Abstract: Lateral power devices where immobile electrostatic charge is emplaced in dielectric material adjoining the drift region. A shield gate is interposed between the gate electrode and the drain, to reduce the Miller charge. In some embodiments the gate electrode is a trench gate, and in such cases the shield electrode too is preferably vertically extended.

Abstract: N-channel power semiconductor devices in which an insulated field plate is coupled to the drift region, and immobile electrostatic charge is also present at the interface between the drift region and the insulation around the field plate. The electrostatic charge permits OFF-state voltage drop to occur near the source region, in addition to the voltage drop which occurs near the drain region (due to the presence of the field plate).

Abstract: Power devices, and related process, where both gate and field plate trenches have multiple stepped widths, using self-aligned process steps.

Abstract: A lateral device includes a gate region connected to a drain region by a drift layer. An insulation region adjoins the drift layer between the gate region and the drain region. Permanent charges are embedded in the insulation region, sufficient to cause inversion in the insulation region.

Abstract: A power MOSFET cell includes an N+ silicon substrate having a drain electrode. A low dopant concentration N-type drift layer is grown over the substrate. An N-type layer, having a higher dopant concentration than the drift region, is then formed and etched to have sidewalls. A P-well is formed in the N-type layer, and an N+ source region is formed in the P-well. A gate is formed over the P-well's lateral channel and has a vertical extension next to the top portion of the sidewalls. A positive gate voltage inverts the lateral channel and increases the conduction along the sidewalls to reduce on-resistance. A vertical shield field plate is also located next to the sidewalls and extends virtually the entire length of the sidewalls. The field plate laterally depletes the N-type layer when the device is off to increase the breakdown voltage.

Abstract: A lateral device includes a gate region connected to a drain region by a drift layer. An insulation region adjoins the drift layer between the gate region and the drain region. Permanent charges are embedded in the insulation region, sufficient to cause inversion in the insulation region.

Abstract: N-channel power semiconductor devices in which an insulated field plate is coupled to the drift region, and immobile electrostatic charge is also present at the interface between the drift region and the insulation around the field plate. The electrostatic charge permits OFF-state voltage drop to occur near the source region, in addition to the voltage drop which occurs near the drain region (due to the presence of the field plate).

Abstract: Methods and systems for power semiconductor devices integrating multiple trench transistors on a single chip. Multiple power transistors (or active regions) are paralleled, but one transistor has a lower threshold voltage. This reduces the voltage drop when the transistor is forward-biased. In an alternative embodiment, the power device with lower threshold voltage is simply connected as a depletion diode, to thereby shunt the body diodes of the active transistors, without affecting turn-on and ON-state behavior.