Browse Prior Art Database

Making Diffused Resistors with Self Isolation

IP.com Disclosure Number: IPCOM000076080D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Vora, MB: AUTHOR

Abstract

This method of forming diffused resistors in an integrated circuit device is compatible with self-isolation fabrication techniques, because the same steps can be used to produce resistors and devices.

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

Making Diffused Resistors with Self Isolation

This method of forming diffused resistors in an integrated circuit device is compatible with self-isolation fabrication techniques, because the same steps can be used to produce resistors and devices.

In this method the surface of P- substrate 10 is oxidized forming a diffusion- mask layer, and two sets of impurities, namely phosphorous and arsenic, are diffused through an opening in the conventional manner to form ultimately the junction isolated region 12 and subcollector region 14, respectively. After the masking layer has been removed from wafer 10 a P epi layer 16 is deposited. Regions 12 and 14 are formed during this operation. A subsequent blanket diffusion of an N type impurity results in a thin N type region 18. Subsequently, a masking layer is deposited on the wafer and diffusion windows opened for forming the base region 20 and the impurity diffused. At the same time windows are made in the masking layer for producing junction isolation regions 22 and 24. Diffused regions are made at the same time that the base diffusion is made. Elongated N type regions 30 are formed which can be used as diffused resistors. The spacing of the resistors is only limited by the photoresist resolution. The emitter region 32 is formed along with the collector contact 34 by an N+ diffusion.

1

Page 2 of 2

2

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