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Field Modulated Punch Through Transistor

IP.com Disclosure Number: IPCOM000078982D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Atwood, BC: AUTHOR [+2]

Abstract

A lateral transistor can be used as a high-density, stable, one-device cell by control of device punch through.

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Field Modulated Punch Through Transistor

A lateral transistor can be used as a high-density, stable, one-device cell by control of device punch through.

The lateral transistor shown comprises a body 10 of P-type material having two identical N-type diffusions 11 and 12 therein, which are separated one from the other by a base region 13.

When a battery 14 is applied between the collector and emitter, junction 15 around region 11 becomes reversed biased and junction 16 around region 12 becomes forward biased. When the width of the base region 13 is insufficient to support the depletion region around the reversed-biased junction 15, such that a voltage independent current flows between the diffusions, the device is said to be in punch through.

However, if a voltage is now applied to the base region 13 by variable-voltage source 17, the forward-biased junction 16 is effectively reversed biased and the device is driven out of punch through, and current ceases to flow. If the voltage applied to the base region 13 by source 17 is a pulsed voltage, then, even after the termination of the pulse, the parasitic capacitors 18 and 19 inherent in the device sustains the effective voltage, preventing the forward-biased junction from returning to the punch-through breakdown state for a period of time, depending on the size of these capacitors and the resistivity of body 10. In the usual case, the decay factor of these junction capacitors is such that the device will return to th...