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Semiconductor Structure for a True Complement Generator

IP.com Disclosure Number: IPCOM000076281D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Lohrey, FH: AUTHOR [+2]

Abstract

True-complement generators are used in address and decode circuitry, particularly in such circuitry for computer memories. In a typical true-complement generator, such as that shown in the block diagram and in the circuit diagram of Fig. 1, it is customary to utilize emitter-follower transistors, such as NPN transistors 10, 11, 12 and 13, the bases of which, respectively designated as 14, 15, 16 and 17, are connected to split collectors 18A and 18B of PNP transistor 18. A similar circuit arrangement is shown in Fig. 2 in which the NPN and PNP transistors are numbered with the same numerals.

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Semiconductor Structure for a True Complement Generator

True-complement generators are used in address and decode circuitry, particularly in such circuitry for computer memories. In a typical true-complement generator, such as that shown in the block diagram and in the circuit diagram of Fig. 1, it is customary to utilize emitter-follower transistors, such as NPN transistors 10, 11, 12 and 13, the bases of which, respectively designated as 14, 15, 16 and 17, are connected to split collectors 18A and 18B of PNP transistor
18. A similar circuit arrangement is shown in Fig. 2 in which the NPN and PNP transistors are numbered with the same numerals.

There is here provided a semiconductor structure for embodying the circuits of fig. 1 or Fig. 2 in a simple and easily fabricated structure shown in plan view in Fig. 3 and in cross-section in Fig. 4. The structure comprises P type substrate 30 having N+ diffusion 31 formed at a surface thereof. Epitaxial layer 32 is grown over P type substrate 30. PNP transistor 18 is a lateral transistor comprising P emitter region 33, epitaxial region 34 as its base, and diffused P region 18B as its collector. Contact is made with base region 34 through contact 19, contact diffusion 38 and subcollector diffusion 31. Diffusion P region 18B also serves as a common-base region for transistors 10 and 11 which further comprise diffused N+ type emitters 36 and 37. N+ region 31 also serves as the collector for these NPN vertical transistors 1...