Westinghouse Electric Corporation

Earl S Schlegel

John Bartko

Derrick J Page

Maurice H Hanes

Chang K Chu

Krishan S Tarneja

An electronic device is provided comprising two or more discrete semiconductor devices in an electrical circuit relationship, hermetically sealed within a single case member. Electrical and thermal conductivity between the semiconductor devices and electrodes on the case member is established and maintained by the application of a compressive force to the case member. The compressive force applied to the case member is distributed to the individual semiconductor devices sealed within the case member.

Compression bonded electronic device comprising a plurality of discrete

A method of reducing the reverse recovery charge of thyristors without substantially increasing forward voltage drop by first determining the depth of the anode PN junction from a major surface adjoining a cathode emitter region. The depth of maximum defect generation in thyristor on irradiation through the major surface with a given radiation source radiating particles with molecular weight greater than one, preferably proton or alpha particles, and adjusting the energy level at the major surface of the thyristor from the radiation source to provide the depth of maximum defect generation adjacent the anode PN junction and preferably in the anode base region within 20 micrometers of the anode PN junction or in the anode emitter region within 15 micrometers of the anode PN junction. Thereafter the thyristor is irradiated through said major surface with the adjusted energy level from the radiation source to a given dosage to reduce the reverse recovery stored charge of the thyristor without substantially increasing the forward voltage drop.

Reducing the reverse recovery charge of thyristors by nuclear irradiation

A four-layer semiconductor thyristor including a planar recombination region extending on both sides of a planar cathode-emitter junction.

Thyristor with continuous recombination center shunt across planar

Irradiated regions are formed in materials such as semiconductor bodies by nuclear radiation where the irradiated regions are of a desired thickness, dosage and dosage gradient, a desired distance from a selected surface of the material. A nuclear radiation beam from a given radiation source radiating particles with molecular weight of at least one (1) is provided that can penetrate the material through a selected surface to a depth greater than the maximum depth of the irradiated region from the selected surface. A beam modifier is formed of a given material and non-uniform shape to modify the energy of the radiation beam on transmission therethrough to form a transmitted radiation beam capable of forming an irradiated region of a desired thickness and dosage gradient in the material a given distance from the selected surface on irradiation of the material through the selected surface with the transmitted radiation beam. The material in which the desired irradiated region is to be formed is positioned with the selected surface thereof to be exposed to the radiation beam from the radiation source on transmission through the beam modifier. The material is thereafter irradiated through the beam modifier and through the selected surface with the radiation beam, preferably while the beam modifier and material are moved relative to each other through a predetermined motion, to form in the material an irradiated region of desired thickness, dosage and dosage gradient, a desired distance from the selected surface. The irradiated region thus formed in semiconductor bodies are particularly of value in changing the electrical characteristics without substantial change of other electrical characteristics.

Forming of contoured irradiated regions in materials such as

A method for making a pnpn semiconductor reverse conducting thyristor comprises the steps of forming n-type semiconductor layers on both sides of a p-type semiconductor substrate for forming an n-type emitter layer and an n-type anode-base layer. A p-type semiconductor impurity region is formed in the n-type anode-base layer for forming a p-type anode layer. A p.sup.+ -type semiconductor layer is ion implanted in the p-type substrate adjacent to the n-type cathode emitter layer by irradiating it with boron atoms.

Method of making ion implanted reverse-conducting thyristor

A photo-transistor includes a multi-apertured collector electrode disposed on a semiconductor collector layer. A laser diode and a light pipe are provided for each aperture such that the light from the laser is transmitted to its associated aperture via the light pipe. Means are included for sequentially pulsing each laser so as to cause a high-frequency intermittent current in the photo-transistor piece of molybdenum 88 which provides improved current flow and heat sinking for the transistor 10.

High-frequency phototransistor operated with multiple light sources

An integrated amplifying gate thyristor is provided with an integral diode in the thyristor structure in the same semiconductor body. The diode provides gate assist turn-off capability with the same gate electrode used to turn-on a pilot thyristor of the device. The common cathode-base region of the pilot and main thyristors also is common with the anode region of the diode. The current gain of the NPN transistor structure formed at the diode and the common anode-base region at the diode is less than the ratio of I.sub.FB /I.sub.g, where I.sub.FB is the forward anode current on triggering the main thyristor into the low impedance conduction state by applying a threshold negative gate assist current (I.sub.G) and an operating anode-cathode load potential, and I.sub.g is a negative gate current selected to assist in turn-off of the main thyristor. Preferably, the current gain of said NPN transistor structure at the diode is controlled by selectively irradiating the diode preferably with electron radiation, by adding a shallow impurity lip to the cathode region of the diode toward the main thyristor, or both.

Integrated gate assisted turn-off, amplifying gate thyristor with narrow

A planar high power Metal-Oxide-Semiconductor-Field-Effect-Transistor (MOSFET) including a substrate with an epitaxial layer on a surface thereof. A gate electrode including a strip of metal extending across a surface of the epitaxial layer and having a plurality of fingers extending therefrom along its length. The gate electrode being electrically insulated from the epitaxial layer by a layer of oxide. A source electrode in the surface of the epitaxial layer including fingers extending therefrom and interdigitating with the fingers of the gate electrode. There are p and n diffusion regions formed in the epitaxial layer except in an area under each of the gate fingers, which area remains undiffused. A drain electrode is connected to the surface of the substrate opposed to the surface upon which the epitaxial layer is deposited. During operation of the MOSFET as the blocking voltage across the transistor increases and the transistor is in the OFF state, the horizontal components of fields from the adjacent and closely spaced p-regions cancel each other so that voltage breakdown due to junction curvature is avoided.

Power metal-oxide-semiconductor-field-effect-transistor

A thyristor having an auxiliary cathode emitter region disposed in the central portion of the device in PN junction relationship with a cathode base region is disclosed. An extra impurity region of the same conductivity type as the cathode base region is disposed in the cathode base region in the central portion of the device inwardly of the outer boundary of the auxiliary cathode emitter. The extra impurity region has a higher impurity density gradient adjacent the common PN junction formed by the cathode and anode base regions than the remainder of such junction.

Thyristor fired by overvoltage

A high speed, high power, four layer, two-terminal silicon diode switch or thyristor designed to be fired by dV/dt induced current is disclosed. The device includes a shunted main cathode emitter, and an auxiliary cathode emitter centrally of the main cathode emitter. The auxiliary cathode emitter is so dimensioned that it is deeper than the main cathode emitter; and the product of (1) the capacitance of the central forward blocking PN junction within the confines of the outer edge of the auxiliary cathode emitter, and (2) the effective radial resistance of the cathode base beneath the auxiliary cathode, and (3) the rate of application of the firing voltage on the anode dV/dt, is at least equal to seven tenths of a volt.

High speed high power two terminal solid state switch fired by dV/dt

Integrated gate assisted turn-off, amplifying gate thyristor, and a

A conventional amplifying gate thyristor is provided with gate assist turn-off capability by a package assembly. The package assembly comprises an encapsulation means adapted for packaging therein the amplifying gate thyristor, said encapsulation means including a locator means for aligning and supporting a gate contact adapted to make ohmic contact with a gate electrode of the amplifying gate thyristor and for aligning and supporting a diode relative to said gate electrode. A diode is disposed in a semiconductor body having cathode and anode regions forming a PN junction therebetween and adjoining opposed major surfaces of said semiconductor body, respectively. The diode is fastened to said locator means with said cathode region thereof making ohmic contact with said gate contact and said anode region thereof making ohmic contact with an anode electrode affixed on a major surface of said semiconductor body and adapted to make ohmic contact with a floating electrode of the amplifying gate thyristor.

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Plum Borough, PA, United States of America

Earl S Schlegel