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Complementary Transistors

IP.com Disclosure Number: IPCOM000075337D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Jacobus, WN: AUTHOR [+2]

Abstract

Complementary NPN and PNP transistors are formed in the same monolithic semiconductor chip by compatible processes.

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Complementary Transistors

Complementary NPN and PNP transistors are formed in the same monolithic semiconductor chip by compatible processes.

Fig. 1 shows an NPN transistor T1 adjacent to a PNP transistor T2. For transistor T2 a P-type layer is diffused into the N+ type subcollector in order to isolate the PNP transistor T2 from the substrate. This structure provides an isolation breakdown voltage of approximately 7 volts.

A breakdown voltage in excess of 30 volts is obtained with the structure of Fig. 2. PNP transistor T2 in Fig. 2 is isolated from the substrate by a first layer of epitaxially deposited N-type material. Also, the N+ type subcollector need not be diffused into those regions of the first N-type epitaxially deposited layer that will have PNP transistors formed therein. A second layer of N-type material is epitaxially deposited over the first layer and the various devices are formed therein. The structure of Fig. 2 requires one extra diffusion and one extra epitaxial layer over the Fig. 1 structure.

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