Abstract: Dielectrically isolated trench fill material is used for the formation of one or more isolated resistor elements within respective ones of a plurality of dielectrically isolated island components in which circuit devices are formed, or in adjacent substrate material. A respective island may have a plurality of trench strip resistor devices, which may have the same or differing resistor values depending upon their geometries or doping concentrations. In addition, the resistor-containing architecture may include one or more conductive cross-unders each defined by a respective cross-under trench strip. A cross-under trench strip contains conductive material, such as heavily doped polysilicon, as opposed to lightly doped polysilicon of the resistor fill material.

Abstract: A high voltage diode having a field plate and substrate separated from a high impurity concentration region by dielectric layers and biased to deplete the high impurity concentration region therebetween before critical field for avalanche is reached for the region.

Abstract: A dielectrically isolated island architecture in which the island is contoured inwardly to form one or more projections that penetrate a well separating two regions in the island to assure that the two regions will be electrically isolated without additional processing steps.

Abstract: A channel stop is self-aligned with a trench sidewall of a trench-isolated semiconductor architecture, so that there is no alignment tolerance between the stop and the trench wall. An initial masking layer, through which the trench pattern is to be formed in a semiconductor island layer, is used as a doping mask for introducing a channel stop dopant into a surface portion of the semiconductor layer where the trench is to be formed. The lateral diffusion of the dopant beneath the oxide and adjacent to the trench aperture defines the eventual size of the channel stop. The semiconductor layer is then anisotropically etched to form a trench to a prescribed depth, usually intersecting the underlying semiconductor substrate. Because the etch goes through only a portion of the channel stop diffusion, leaving that portion which has laterally diffused beneath-the oxide mask, the channel stop is self-aligned with the sidewall of the trench.

Abstract: A biasing method for and IC with enhanced reverse bias breakdown. A field plate covering the surface PN junction and extending laterally therefrom is biased to partially deplete the island under the field plate and the substrate supporting the island is biased to complete the total depletion of the island under the field plate, establishing a substantially merged vertical field at less than critical for avalanche. Because most of the charge is required to support the vertical component of the field, the rate of change in the horizontal component is small per unit of additional terminal voltage and the lateral extension of the field plate increases the breakdown voltage beyond the plane breakdown for a PN junction of a given doping profile.

Abstract: Dual polarity source/drain extensions are formed simultaneously in both PMOS and NMOS devices of a CMOS architecture using a common set of implants, so to be contiguous with one or both of source and drain regions of both the PMOS and the NMOS structures. The complementary conductivity lateral extension region configuration may be either an N over P or a P over N structure. The dual implant methodology can be carried out with no explicit masking steps, yielding MOS device which have source/drain extension regions that are self aligned to the gate and have minimal overlap capacitance.

Abstract: The occupation area and thickness of dielectrically isolated island-resident transistor structures, which employ a buried subcollector for providing low collector resistance at the bottom of the island, are reduced by tailoring the impurity concentration of a reduced thickness island region to provide a low resistance current path from an island location directly beneath the base region to the collector contact. The support substrate is biased at a voltage which is less than the collector voltage, so that the portion of the collector (island) directly beneath the emitter projection onto the base is depleted of carriers prior to the electric field at that location reaching BCVEO, so as not to effectively reduce BVCEO.

Abstract: Region forming steps or interconnect-forming steps through which low voltage CMOS devices are formed in a semiconductor wafer are also employed to simultaneously form one or more regions or layers at selected sites of a substrate where high voltage devices are to be formed. Such selective modification of an already existing mask set designed for low voltage CMOS topography allows additional doping of the substrate or provision of further overlay material to accommodate the effects of high voltage operation of selected areas of the water and thereby effectively performs precursor tailoring or modification of those portions of the wafer where a high voltage condition will be encountered.

Abstract: A MESFET wherein a Schottky top gate which extends across the channel region between the source and drain regions and beyond sides of the dielectric isolation in which the device is built at two points. The bottom gate also extends beyond the dielectric isolation below the surface of the island and intersects the bottom of the source and drain regions. Where a bottom gate contact region forms an annulus encompassing the source and drain, the top gate extends across the channel and only onto sides of the bottom gate contact region at two points. The source and drain regions which are formed are sufficiently spaced from the dielectric isolation so as not to effect the I.sub.DSS resulting from variation in the island size.

Abstract: The thickness of a DI island structure is reduced and the performance of bipolar and JFET structures enhanced by shaping the bottom of the DI island during anisotropic etching to define isolated islands, so that the resulting structure contains one or more projections whose separation from the topside diffusion predefines operational characteristics of the device. If the projection is directly beneath the bottom of a gate diffusion, pinch-off voltage of a JFET device is reduced without substantially affecting channel resistance. When the projection is positioned so that its inclined surface extends alongside the curvilinear PN junction formed between the gate diffusion and the island, channel thickness and sensitivity of channel thickness to viriations in island thickness are reduced.

Abstract: The trench pattern of a dielectrically isolated island architecture is filled with doped polysilicon and used as an interconnect structure for circuit devices that are supported within the islands, thereby decreasing the amount of topside interconnect and reducing the potential for parasitics beneath tracks of surface metal. The trench pattern may serve as a voltage distribution network or provide crossunders beneath surface tracks. In addition, at least one of the islands may contain one or more auxiliary poly-filled trench regions to perform the crossunder function. Such an auxiliary trench region may be also provided in an island that contains a circuit device. Manufacture of the conductor-filled trench structure may be facilitated by depositing polysilicon over a dielectrically coated trench grid structure and then planarizing the polysilicon to the surface of the oxide dielectric. The exposed polysilicon is doped and then oxidized to seal the dopant, which forms a thin oxide layer on the poly.

Abstract: A dielectrically isolated island architecture in which the island is contoured inwardly to form one or more projections that penetrate a well separating two regions in the island to assure that the two regions will be electrically isolated without additional processing steps.

Abstract: The present invention provides an improved lateral drift region for both bipolar and MOS devices where improved breakdown voltage and low ON resistance are desired. A top gate of the same conductivity type as the device region with which it is associated is provided along the surface of the substrate and overlying the lateral drift region. In an MOS device, the extremity of the lateral drift region curves up to the substrate surface beyond the extremity of the top gate to thereby provide contact between the JFET channel and the MOS channel.

Abstract: A channel stop is self-aligned with a trench sidewall of a trench-isolated semiconductor architecture, so that there is no alignment tolerance between the stop and the trench wall. An initial masking layer, through which the trench pattern is to be formed in a semiconductor island layer, is used as a doping mask for introducing a channel stop dopant into a surface portion of the semiconductor layer where the trench is to be formed. The lateral diffusion of the dopant beneath the oxide and adjacent to the trench aperture defines the eventual size of the channel stop. The semiconductor layer is then anisotropically etched to form a trench to a prescribed depth, usually intersecting the underlying semiconductor substrate. Because the etch goes through only a portion of the channel stop diffusion, leaving that portion which has laterally diffused beneath the oxide mask, the channel stop is self-aligned with the sidewall of the trench.

Abstract: A voltage divider including a plurality of series connected depletion mode field effect transistors having their gates and sources biased to operate in saturation mode for the operating range of the divider. Preferably, the gates and sources are connected together. A series resistor adjusts the value of the divider element. A parallel resistor defines the output resistance of the divider element. The voltage divider may be used as a biasing network for stacked transistors. A buffer may be provided between the voltage divider and the control terminal of the stacked transistors. The voltage divider may be used to bias follower stages and the input stages of an operational amplifier.

Abstract: The trench pattern of a dielectrically isolated island architecture is filled with doped polysilicon and used as an interconnect structure for circuit devices that are supported within the islands, thereby decreasing the amount of topside interconnect and reducing the potential for parasitics beneath tracks of surface metal. The trench pattern may serve as a voltage distribution network or provide crossunders beneath surface tracks. In addition, at least one of the islands may contain one or more auxiliary poly-filled trench regions to perform the crossunder function. Such an auxiliary trench region may be also provided in an island that contains a circuit device. Manufacture of the conductor-filled trench structure may be faciliated by depositing polysilicon over a dielectrically coated trench grid structure and then planarizing the polysilicon to the surface of the oxide dielectric. The exposed polysilicon is doped and then oxidized to seal the dopant, which forms a thin oxide layer on the poly.

Abstract: A MESFET including a Schottky top gate which extends across the channel region between the source and drain regions and beyond two opposed sides of the dielectric isolation onto the substrate in which the device is built. The portion of the top gate which extends across the channel is disconnected from the portion which extends across the substrate beyond the dielectric isolation. This may result from the removal of the gate material at the dielectric isolation or by the portion of the gate material which is on the dielectric isolation being vertically displaced and disconnected or discontinous from the portion of the gate material which extends across the channel and that portion which extends across the substrate.

Abstract: Series resistance in the low impurity portion of a high breakdown PN junction of a three or four layer device is reduced by providing an increased inpurity region at the junction of the same conductivity type as the low impurity portion and having an impurity profile such that the increased impurity region is depleted under reverse biasing before critical field is reached therein. The three layer devices include insulated gate field effect transistors and bipolar devices and the four layer device is a semiconductor controlled rectifier (SCR).

Abstract: The trench pattern of a dielectrically isolated island architecture is filled with doped polysilicon and used as an interconnect structure for circuit devices that are supported within the islands, thereby decreasing the amount of topside interconnect and reducing the potential for parasitics beneath tracks of surface metal. The trench pattern may serve as a voltage distribution network or provide crossunders beneath surface tracks. In addition, at least one of the islands may contain one or more auxiliary poly-filled trench regions to perform the crossunder function. Such an auxiliary trench region may be also provided in an island that contains a circuit device. Manufacture of the conductor-filled trench structure may be facilitated by depositing polysilicon over a dielectrically coated trench grid structure and then planarizing the polysilicon to the surface of the oxide dielectric. The exposed polysilicon is doped and then oxidized to seal the dopant, which forms a thin oxide layer on the poly.

Abstract: A MESFET wherein a Schottky top gate which extends across the channel region between the source and drain regions and beyond sides of the dielectric isolation in which the device is built at two points. The bottom gate also extends beyond the dielectric isolation below the surface of the island and intersects the bottom of the source and drain regions. Where a bottom gate contact region forms an annulus encompassing the source and drain, the top gate extends across the channel and only onto sides of the bottom gate contact region at two points. The source and drain regions which are formed are sufficiently spaced from the dielectric isolation so as not to effect the I.sub.DSS resulting from variation in the island size.