Northrop Grumman Systems Corporation

Westinghouse Electric Corporation

Saptharishi Sriram

Rowland C Clarke

Robert Miles Young

Carl Baldwin Freidhoff

Richard R Siergiej

Joseph C Kotvas

A silicon carbide metal semiconductor field effect transitor fabricated on silicon carbide substrate with a layer which suppresses surface effects, and method for producing same. The surface-effect-suppressive layer may be formed on exposed portions of the transistor channel and at least a portion of each contact degenerate region. The surface-effect-suppressive layer may be made of undoped silicon carbide or of an insulator, such as silicon dioxide or silicon nitride. If the surface-effect-suppressive layer is made of silicon dioxide, it is preferred that the layer be fabricated of a combination of thermally-grown and chemical vapor deposition deposited silicon dioxide.

Silicon carbide power MESFET with surface effect supressive layer

A semiconductor wafer and a method of forming vias in a semiconductor wafer having opposite first and second planar surfaces and predetermined thickness includes forming a plurality of first channels of first predetermined depth along a first direction in the first planar surface of the semiconductor wafer and forming a plurality of second channels of second predetermined depth along a second direction in the second planar surface of the semiconductor wafer. The first and second predetermined depths of the channels are selected such that vias are formed through the semiconductor wafer. The channels may be formed by saw cutting or scribing the planar surfaces of the semiconductor wafer. A plurality of circuit devices may be formed on the first planar surface of the semiconductor wafer prior to forming the plurality of first and second channels. A metallic layer is deposited within the vias and on the first and second planar surfaces to provide electrical connection between the circuit devices and the second planar surface of the semiconductor wafer through the vias.

Integrated circuit non-etch technique for forming vias in a

The invention provides for a field effect transistor (FET) which includes a substrate and a buffer layer formed upon the substrate and an active layer formed upon the buffer layer. The active layer includes a gate region, drain region and source region. In addition, a channel region is formed in the active layer intermediate the source region and drain region. The channel region includes a first portion of reduced thickness adjacent the drain region. The active layer may include a recess adjacent the drain region to provide the thin channel region. Preferably, the thickness of the first portion of the channel region is equal to the undepleted channel thickness within the second portion of the channel region adjacent the first portion. The substrate, buffer layer, active layer, and degenerate layers are preferably fabricated of silicon carbide or gallium nitride. Further, the FET preferably includes a p type buffer, n type active layer, and n+ degenerate layers. The FET may also include a surface-effect-suppressive layer which preferably covers portions of the active layer and the degenerate layers.

Silicon carbide power field effect transistor

A static induction transistor fabricated of silicon carbide, preferably 6H polytype, although any silicon carbide polytype may be used. The preferred static induction transistor is the recessed Schottky barrier gate type. Thus, a silicon carbide substrate is provided. Then, a silicon carbide drift layer is provided upon the substrate, wherein the drift layer has two spaced-apart protrusions or fingers which extend away from the substrate. Each protrusion of the drift layer has a source region of silicon carbide provided thereon. A gate material is then provided along the drift layer between the two protrusions. A conductive gate contact is provided upon the gate material and a conductive source contact is provided upon each source region. A conductive drain contact is provided along the substrate. Other gate types for the static induction transistor are contemplated. For example, a planar Schottky barrier gate may be employed. Furthermore, recessed or planar MOS gates may be utilized, as may a PN junction gate.

Silicon carbide static induction transistor

A solid state mass spectrograph includes an inlet, a gas ionizer, a mass filter and a detector array all formed within a cavity in a semiconductor substrate. The gas ionizer can be a solid state electron emitter with ion optics provided by electrodes formed on apertured partitions in the cavity forming compartments through which the cavity is evacuated by differential pumping. The mass filter is preferably a Wien filter with the magnetic field provided by a permanent magnet outside the substrate or by magnetic film on the cavity walls. The electric field of the Wien filter is provided by electrodes formed on walls of the cavity. The detector array is a linear array oriented in the dispersion plane of the mass filter and includes converging electrodes at the end of the cavity serving as Faraday cages which pass charge to signal generators such as charge coupled devices formed in the substrate but removed from the cavity.

Solid state micro-machined mass spectrograph universal gas detection

An undoped surface layer over and lattice matched to the n-channel layer between the gate contact and the spaced apart source and drain n+ regions in power FETs made of group III-V compounds minimizes surface effects that preclude such devices from operating efficiently at high voltages, and improves reliability. The undoped surface layer may be grown on the n-channel layer before the layer forming the n+ regions, or where the n+ regions can be formed in the undoped surface layer. The invention is especially suitable for GaAs MESFETs and HEMTs.

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Monroeville, PA, United States of America

Saptharishi Sriram