Abstract: A high voltage MOSFET with low on-resistance and a method of lowering the on-resistance for a specific device breakdown voltage of a high voltage MOSFET. The MOSFET includes a blocking layer of a first conductivity type having vertical sections of a second conductivity type or the blocking layer may include alternating vertical sections of a first and second conductivity type.

Abstract: A high voltage MOSFET with low on-resistance and a method of lowering the on-resistance for a specific device breakdown voltage of a high voltage MOSFET. The MOSFET includes a blocking layer of a first conductivity type having vertical sections of a second conductivity type or the blocking layer may include alternating vertical sections of a first and second conductivity type.

Abstract: A method of fabricating a UMOS semiconductor device includes a blanket implant of an N type dopant into a surface of a substrate (for forming source regions), a high energy implant of a P type dopant into the substrate (for forming body regions), an etch through a hard mask to form trenches and mesas (each of the mesas having a source region at its top and a body region below), and concurrently (i) providing a gate dielectric on the sidewalls of the trenches and (ii) redistributing the dopants so that the body regions extend deeper into the substrate beneath the centers of the mesas than adjacent the walls of the trenches. Contact windows are etched in the mesas to allow electrical contact with the source regions and the body regions. The initial implant of P type dopant may be a blanket implant or an implant through a mask which concentrates the P type dopant in the centers of the mesas.

Abstract: A pattern for a wafer for a MOS-gated semiconductor device includes plural ribbons extending from a source contact region to another source contact region, each of the ribbons having a single source region between two channel regions, so as to increase the device's current-carrying capability per unit area relative to the prior art. The pattern increases the size of the active current-carrying area (the channel and neck regions of the device) relative to the area of the source contact areas. The source contact regions may be discrete or linear, and the ribbons may extend therefrom perpendicularly or at other angles.

Abstract: The performance of COMFET-based electrical switches may be improved by connecting a MOSFET substantially in parallel with the COMFET. In a monolithic embodiment, a MOSFET drain region may be added to a surface of a COMFET and shorted to the emitter region of the COMFET. The invention decreases the turn-off time of the COMFET, reduces the discontinuity at current direction reversal and increases the latch-up current of a semiconductor switch.

Abstract: The sensitivity of breakdown voltage to temperature and dV/dT induced currents is reduced in semiconductor power devices having a wide base transistor. The sensitivity is reduced by diverting current from the emitter of the wide base transistor to the base of the wide base transistor (an emitter short that does not reduce breakdown voltage) or by injecting a current into the base of the wide base transistor to its collector (an injected current that may lower the breakdown voltage, but no more than that related to temperature and capacitive current). The invention finds application in both epitaxial grown and substrate based devices.

Abstract: A MOS-gated semiconductor device may be manufactured by a process in which the neck region of the device is doped through a previously deposited polysilicon gate. In the method of the present invention, the dopant in the neck region of the device is not subjected to the same temperature history as the body dopant, thereby providing means to increase the ruggedness of the device and providing means by which the threshold voltage of the device may be controlled.

Abstract: A pattern for a wafer for a MOS-gated semiconductor device includes plural ribbons extending from a source contact region to another source contact region, each of the ribbons having a single source region between two channel regions, so as to increase the device's current-carrying capability per unit area relative to the prior art. The pattern increases the size of the active current-carrying area (the channel and neck regions of the device) relative to the area of the source contact areas. The source contact regions may be discrete or linear, and the ribbons may extend therefrom perpendicularly or at other angles.

Abstract: Semicondctor devices having a curved P-N junction in an active area of the device and an edge passivation region extending from the active area to an edge region of the device include an electrically resistive ribbon that spirals outwardly from the active area to the edge of the device so that a voltage difference between the active area and the edge region is spread along the length of the ribbon. The ribbon may take the form of a linear resistor or may include plural diodes. The distance between radially overlapping portions of the spiralling ribbon and the cross-sectional area of the ribbon may be varied to spread the equipotential lines in the device so as to reduce the effect of the curved P-N junctions on the breakdown voltage of the device.

Abstract: In a power FET composed of a substrate having upper and lower surfaces, the FET providing a current flow path between the upper and lower surfaces, and the FET having a plurality of drain regions extending to the substrate upper surface and an insulated gate electrode disposed on the upper surface, the improvement wherein said drain regions are disposed in a hexagonal lattice pattern, and said gate electrode comprises: a plurality of gate segments each covering a respective drain region; and a plurality of connecting segments each connecting together three of said gate segments.

Abstract: In a power FET composed of a substrate having upper and lower surfaces and having a semiconductor body providing a current flow path between the upper and lower surfaces and having at least one body region of a first conductivity type which extends to said upper surface; and at least one base region extending into the substrate from the upper surface, the base region being of a second conductivity type opposite to the first conductivity type, the base region being at least partially disposed in the current flow path and having at least two portions between which the at least one body region extends, and the FET further having an insulated gate disposed at the upper surface above the body region, the substrate further has a shielding region of the second conductivity type extending into the at least one body region from the upper surface, at a location below the gate electrode and enclosed by the base region portions, and spaced from the base region by parts of the body region of the first conductivity type.

Abstract: In a power FET composed of a substrate having upper and lower surfaces and having a semiconductor body of a first conductivity type, the body providing a current flow path between the upper and lower surfaces and having at least one body region which extends to said upper surface; and at least one base region extending into the substrate from the upper surface, the base region being of a second conductivity type opposite to the first conductivity type and having an upper portion located adjacent the upper surface of the substrate and a lower portion separated from the upper surface of the substrate by the upper portion, the upper portion defining a channel which is disposed in the current flow path adjacent the upper surface of the substrate, and the FET further having an insulated gate disposed at the upper surface above the body region, an impurity layer region extends into the channel from the upper surface of the substrate for giving the channel a lower impurity density than the lower portion of the base

Abstract: A monolithic semiconductor device comprises a VDMOS transistor having first and second main electrodes and a control electrode, and a lateral MOSFET having first and second main electrodes and a control electrode, wherein one of the first and second electrodes of the lateral MOSFET has a lower doping concentration than that of the first and second main electrodes of the VDMOS transistor for forming a Schottky barrier diode.

Abstract: A VDMOS device includes a wafer of semiconductor material having first and second opposed major surfaces. A drain region of a first conductivity type extends along the one major surface. A plurality of body regions of a second conductivity type is in the body region at the one major surface. Each body region forms with the drain region a body/drain PN junction, the intersection of which with the first major surface is in a closed path, preferably a hexagon. A plurality of spaced source regions of the one conductivity type are in each of the body regions with each source region being positioned opposite the space between two source regions in the adjacent body region. Each source region forms with the body region a source/body PN junction. A portion of each of the source/body PN junctions is adjacent to but spaced from its respective drain/body PN junction to form a channel region therebetween. An insulated gate is over the first major surface and the channel regions.

Abstract: A power MOS transistor, including source, drain, and gate electrodes, comprises a substrate of a semiconductor material of one conductivity type having first and second opposed surfaces; a drain region extending through the substrate between the surfaces; a plurality of spaced body regions of the opposite conductivity type extending into the substrate from the first surface; and a source region of the one conductivity type extending into the substrate from the first surface within each of the body regions, the interface of each of the source regions with its respective body region at the first surface being spaced from the interface of its respective body region and the drain region at the first surface to form a channel region therebetween. A gate electrode overlies and is insulated from the first surface and extends across the channel regions. A conductive electrode extends over and is insulated from the gate electrode, and contacts at least a portion of the source regions.

Abstract: The present invention relates to a power MOS transistor having a current limiting circuit incorporated in the same substrate as the transistor. The power MOS transistor includes a drain region extending through the substrate between opposed first and second surfaces, a plurality of body regions in the substrate at the first surface, a separate source region in the substrate at the first surface within each body region and a channel extending across each body region between its junction with its respective source region and its junction with the drain region. A conductive gate is over and insulated from the first surface and extends over the channel regions. A first conductive electrode extends over and is insulated from the gate and contacts a first portion of the source regions. A second conductive electrode extends over and is insulated from the gate and contacts a second portion of the source regions. The second portion contains a smaller number of the source regions than the first portion.

Abstract: A MOSFET device comprises a semiconductor wafer which includes a drain region of first conductivity type contiguous with a wafer surface. A diffused body region of second conductivity type extends into the wafer from the wafer surface so as to form a body/drain PN junction which has a polygonally-shaped intercept at the wafer surface. A plurality of source regions of first conductivity type extends into the wafer from the wafer surface within the boundary of the body region. The source regions define a plurality of channel regions, a contact area, and at least one shunt region at the surface of the body region. Each shunt region extends from the contact area to one of the corners of the body/drain PN junction polygonal intercept. A source electrode contacts the body region contact area and each of the source regions adjacent thereto.

Abstract: An IGFET device includes a semiconductor wafer having a first conductivity type drain region contiguous with a wafer surface. A second conductivity type body region extends into the wafer from the wafer surface so as to form a body/drain PN junction having an intercept at the surface; the body region further including a body-contact portion of relatively high conductivity disposed at the surface. A first conductivity type source region extends into the wafer so as to form a source/body PN junction which has first and second intercepts at the surface. The first intercept is spaced from the body/drain intercept so as to define a channel region in the body region at the surface, and the second intercept is contiguous with the body contact portion. The second intercept is relatively narrowly spaced from the first intercept along most of the length of the first intercept and is relatively widely spaced from the first intercept at one or more predetermined portions.

Abstract: A VDMOS device comprises a semiconductor wafer having a major surface with a first conductivity type drain region thereat. An array of second conductivity type body regions, spaced from each other by distance D, is diffused into the drain region from the first surface. The body regions each include a relatively high conductivity supplementary body region and a first conductivity type source region diffused therein from within the first surface boundary thereof. The spacing between each source region and the drain region defines a channel region at the first surface. A source electrode contacts the source and body regions and an insulated gate electrode overlies each channel region. A gate bond pad, in direct contact with the gate electrode, overlies a second conductivity type gate shield region and is insulated therefrom. The gate shield region is contiguous with the drain region and is spaced from the neighboring channel regions by distance D.

Abstract: A vertical MOSFET device includes a major surface having an active, gate-controlled portion adjacent to an inactive portion. A gate-controlled perimeter channel is disposed at the boundary between the active and inactive portions.