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Browse Prior Art Database

Emitter Structure with Different Impurity Concentrations

IP.com Disclosure Number: IPCOM000085852D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Aggarwal, BK: AUTHOR

Abstract

The advantages of a concentration gradient in an emitter structure are described in an article "A Novel Bipolar Device With Low Emitter Impurity Concentration Structure" by H. Yagi, Et Al, IEEE Device Proceedings, pages 262-265, distributed at the meeting in Washington, D.C., December 1974. The emitter structure of the article is adapted for linear integrated circuits by ion implantation and diffusion techniques.

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Emitter Structure with Different Impurity Concentrations

The advantages of a concentration gradient in an emitter structure are described in an article "A Novel Bipolar Device With Low Emitter Impurity Concentration Structure" by H. Yagi, Et Al, IEEE Device Proceedings, pages 262-265, distributed at the meeting in Washington, D.C., December 1974. The emitter structure of the article is adapted for linear integrated circuits by ion implantation and diffusion techniques.

The figure shows a vertical profile of a linear integrated circuit practicing the present process steps. An N-type emitter is formed from phosphorus and arsenic impurities as shown by regions 10 and 12. The remainder of the linear integrated device is formed from boron impurities in the base region as shown by region 14, and an N- epi structure 16 including an N+ subcollector region 18. The regions 14, 16 and 18 are formed by conventional planar epitaxial techniques.

The emitter regions 10 and 12 may be formed by several alternatives.

One alternative is to form the arsenic region 10 by an ion implant at 50 Kev and a dosage of 8 x 10/15/ ions per cm/2/. The arsenic implant is followed by an anneal at 1050 degrees C for fifty minutes. The phosphorus region 12 is formed by an ion implant at 150 Kev energy and 2.6 x 10/15/ dosage. An anneal is performed at 970 degrees C for 200 minutes to achieve the vertical profile of the figure.

Another alternative is to perform the arsenic implant of the first alte...