Bell Telephone Laboratories

At&t Bell Laboratories

Pacific Bell

Robert S Scott

James E Kohl

Adrian R Hartman

Peter W Shackle

Yiu-Huen Wong

Eric J Wildi

Michael S Adler

William F MacPherson

Harry T Weston

Deva N Pattanaya

William L Buchanan, Jr

An area saving dielectrically isolated semiconductor structure is disclosed which allows for the merger of a plurality of active devices, which share a common terminal, in a single dielectrically isolated (DI) island, or tub. In particular, an isolation groove is formed in the bottom of the DI tub and extends upwards toward the top surface of the semiconductor structure. The common diffusion region associated with the common terminal is located in the DI tub directly over the isolation groove. The isolation groove and common diffusion region thus separate the single DI tub into isolated sections, where a separate active device can be formed in each section. Isolation is achieved through the interaction of the groove with the common diffusion region to 'pinch off' the conductive channel between devices in the DI tub. In a preferred embodiment, an inverted V-shaped isolation groove is utilized so as not to complicate the fabrication process. In order to merge a large plurality of devices in a single DI tub, a plurality of isolation grooves may be utilized to divide the single DI tub into a number of separate isolated sections.

Inverted groove isolation technique for merging dielectrically isolated

An integrated circuit in which a large potential can be maintained between the source of the device and the substrate on which this device and other devices are fabricated is described. The circuit employs a minority carrier sink region to remove minority carriers from the gate region of a MOS depletion device. The sink region is shielded from the substrate by a buried layer which prevents punch-through between the sink region and the substrate.

High-voltage pull-up device

A circuit for driving an output between two voltage states in response to a control signal is disclosed. The circuit requires a very small amount of power in its quiescent state. The circuit comprises a first switch including first and second control terminals that provides a conductive path from a first source of potential to an output terminal when the potential difference between the control terminals is less than a first predetermined threshold value and for electrically isolating the first source of potential from the output terminal when the potential difference between the control terminals is greater than the first predetermined threshold value, and a second switch that provides a conductive path between a second source of potential and the output terminal when the first switch electrically isolates the first source of potential from the output terminal. The second switch electrically isolates the output terminal from the second source of potential when the first switch provides a conductive path from the first source of potential to the output terminal. The circuit also includes a control circuit for causing the potential difference between the first and second control terminals of the first switch to be greater than the first threshold value in response to a predetermined signal on the circuit input terminal and causes the potential difference between the first and second control terminals of the first switch to be less than the first threshold value when the predetermined signal is not present on the circuit input terminal.

Low power high voltage driver circuit

The present invention relates to an improved Schottky barrier device wherein the leakage current present in the reverse bias mode attributed to the presence of an electric field at the Schottky barrier (18) is significantly reduced by the inclusion of one or more field shields (22), P.sup.+ -type diffusions located under the metal anode (16) of the Schottky barrier device at the Schottky barrier (18). The P.sup.+ -type field shields, which are disposed in a pattern on the surface of the Schottky barrier, reduce the surface electric field present, thereby significantly reducing the leakage current related thereto.

Field shields for Schottky barrier devices

A solid-state protector circuit utilizes the combination of two zener diodes (Z1, Z2), a resistor (R1), a capacitor (C1), and a gated diode switch (GDS) to facilitate the rapid discharge of high voltage transients.

Solid-state protector circuitry using gated diode switch

A high voltage solid-state switch uses a dielectrically isolated lightly doped p- type semiconductor body with a heavily doped p+ type anode region, a heavily doped n+ type gate region, a moderately doped p type shield region, and a heavily doped n+ type cathode region. The shield region surrounds the cathode region. Separate electrodes contact the anode, gate, shield, and cathode regions. The gate and cathode regions also act as the collector-emitter output circuitry of an n-p-n transistor with the shield region acting as the base. With the shield (base) region forward-biased with respect to the cathode or gate regions, the n-p-n transistor is biased on and the collector and emitter are rapidly pulled close to each other in potential. With proper operating potentials applied to the anode and cathode regions, the switch rapidly assumes an 'ON' state when the potential of the shield (base) region is set to a level which biases the n-p-n transistor ON. The integral n-p-n transistor serves to rapidly turn the switch to the ON state and only marginally increases the amount of silicon area needed to implement the switch.

Growing community of inventors

New Providence, NJ, United States of America

Robert S Scott