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Current Gain in Injection Transistor Structures

IP.com Disclosure Number: IPCOM000083391D
Original Publication Date: 1975-May-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Berger, HH: AUTHOR [+2]

Abstract

By using lateral PNP transistors as load elements in flip-flop storage cells (cf., e.g., IBM Technical Disclosure Bulletin Vol. 14, No. 6, November 1971, p. 1720) area saving low-power integrated circuits are obtained. The same applies to merged transistor logic (MTL) or integrated injection logic (I/2/L) circuit structures.

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Current Gain in Injection Transistor Structures

By using lateral PNP transistors as load elements in flip-flop storage cells (cf., e.g., IBM Technical Disclosure Bulletin Vol. 14, No. 6, November 1971, p. 1720) area saving low-power integrated circuits are obtained. The same applies to merged transistor logic (MTL) or integrated injection logic (I/2/L) circuit structures.

The current gain of a lateral PNP transistor is primarily governed by the injection current via the parasitic junction at the emitter bottom. The proportion of this vertical injection current must, as a rule, be small in relation to the lateral injection current into the collector regions arranged laterally to the emitter.

According to the IEEE Journal of Solid-State Circuits, Vol. SC-9, No. 5, October 1974, pp. 218 to 227 there are different conditions for the vertical injection of electrons into the P (emitter) region: contact covered P region (injection current density jnc) and oxide covered P region (injection density jno). It has been found that jnc: jno shows approximately a 10:1 relationship. From this it is proposed to provide, especially in a multicollector structure, the central emitter injector region with a relatively small contact. In other words, the emitter contact area is to be designed small relative to the emitter surface area.

The drawing shows schematically, a lateral PNP transistor with P emitter region 1 diffused or implanted into N (epitaxial) base region 2, and with four...