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Browse Prior Art Database

Gate Controlled Bistable Bipolar Transistor

IP.com Disclosure Number: IPCOM000081959D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Dalal, HM: AUTHOR [+2]

Abstract

A negative resistance bipolar transistor can be obtained by introducing a cross-coupled field-effect transistor (FET)(enhancement mode) within the base surface area of the bipolar transistor. Fig. 1 is the cross section of an N channel FET comprising N+ regions 1 and 2 within P pocket 3 in N- substrate 4. A vertical NPN bipolar transistor is formed by adding P+ base contact 5 and N+ collector contact 6 to the existing structure.

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Gate Controlled Bistable Bipolar Transistor

A negative resistance bipolar transistor can be obtained by introducing a cross-coupled field-effect transistor (FET)(enhancement mode) within the base surface area of the bipolar transistor. Fig. 1 is the cross section of an N channel FET comprising N+ regions 1 and 2 within P pocket 3 in N- substrate 4. A vertical NPN bipolar transistor is formed by adding P+ base contact 5 and N+ collector contact 6 to the existing structure.

The bipolar transistor is cross-coupled to the FET by the addition of connections 7 and 8, whereby the base 5 of the bipolar transistor is connected to the drain 1 of the FET, and the gate 9 of the FET is connected to the collector 6 of the bipolar transistor. The source of the FET and the emitter of the bipolar transistor are formed by the same N+ region 2.

Fig. 2 depicts the typical negative resistance characteristic which is obtained on a curve tracer, when the structure of Fig. 1 is operated as a bipolar transistor. The negative resistance occurs when the collector voltage (also the FET gate voltage) exceeds the threshold voltage of the FET. The resultant "turn on" of the FET effectively shorts the emitter-base junction of the bipolar transistor and abruptly reduces the collector current (Ic) to zero.

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