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Bipolar Transistor Process using Plural Apertured Mask for Base and Emitter Diffusions

IP.com Disclosure Number: IPCOM000080072D
Original Publication Date: 1973-Oct-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Parisi, JA: AUTHOR

Abstract

A lateral bipolar transistor characterized by a very narrow and closely controlled base is fabricated, using the same plural-apertured diffusion mask for making base and emitter diffusions. All of the apertures are employed during the base diffusion, whereas some, but not all, of the same mask apertures are used for making the subsequent emitter diffusion.

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Bipolar Transistor Process using Plural Apertured Mask for Base and Emitter Diffusions

A lateral bipolar transistor characterized by a very narrow and closely controlled base is fabricated, using the same plural-apertured diffusion mask for making base and emitter diffusions. All of the apertures are employed during the base diffusion, whereas some, but not all, of the same mask apertures are used for making the subsequent emitter diffusion.

The figure represents a simplified plan view of a lateral bipolar transistor having interdigitated emitter and base contacts and emitter and base regions, formed by using different combinations of apertures in the same diffusion mask. All of the apertures 1-5 are employed during base diffusion producing a base- collector junction 6. Apertures 1, 3 and 5 are blocked off during the subsequent emitter diffusion. The use of only apertures 2 and 4 produce the emitter-base junctions 7 and 8.

Base width W in the active region of the transistor is closely controlled by the Dt parameters employed in the successive base and emitter diffusions. Interdigitated base and emitter contacts in areas 1, 3, 5 and areas 2, 4, respectively, are applied along with collector contact 9 to complete the structure.

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