Browse Prior Art Database

Diffusion Front Tailoring

IP.com Disclosure Number: IPCOM000077209D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Berger, HH: AUTHOR [+2]

Abstract

Diffusion regions of the same conductivity type, but of different depths are diffused into monolithic semiconductor structures in a single-diffusion step. To this end, the semiconductor body is initially etched to a depth corresponding to the difference in depth of the diffusion regions in those areas in which the diffusion regions of the greater depth are to be formed.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Diffusion Front Tailoring

Diffusion regions of the same conductivity type, but of different depths are diffused into monolithic semiconductor structures in a single-diffusion step. To this end, the semiconductor body is initially etched to a depth corresponding to the difference in depth of the diffusion regions in those areas in which the diffusion regions of the greater depth are to be formed.

The figure shows the structure of a bipolar transistor in which isolation regions 1 and 2 and base region 3 are formed in a single-diffusion step. While base region 3 penetrates epitaxial layer 4 only partly, isolation regions 1 and 2 must extend through the layer down to substrate 5. Before P-diffusion the semiconductor material, in the areas in which isolation regions 1 and 2 are to be subsequently formed, is etched down to a depth corresponding to the difference in depth of the isolation regions and the base region in the semiconductor body.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]