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Control of the Temperature Coefficient of Resistance of High Value Implanted Resistors

IP.com Disclosure Number: IPCOM000052903D
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 3 page(s) / 76K

Publishing Venue

IBM

Related People

Keenan, WA: AUTHOR [+3]

Abstract

High value resistors, when fabricated by diffusion, take up considerable space in integrated circuits. For LSI circuits, high value resistors can be fabricated by the conventional method, modified only in that ion implantation is used.

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Control of the Temperature Coefficient of Resistance of High Value Implanted Resistors

High value resistors, when fabricated by diffusion, take up considerable space in integrated circuits. For LSI circuits, high value resistors can be fabricated by the conventional method, modified only in that ion implantation is used.

For this purpose, high value resistors were fabricated on 57 mm wafers by ion implantation of arsenic, boron and phosphorous, at energy levels from 50 to 150 KeV. Ion-implanted resistors so inamplanted exhibit a positive temperature coefficient of resistance (TCR) that increases with increasing sheet resistance. It has been found that the TCR for phosphorous and boron, at three different energy levels, are very similar. The TCR values for arsenic are somewhat lower than for phosphorous and boron.

As can be seen by the respective plots for boron, phosphorous and arsenic in Figs. 1-3, it is apparent that for a low value resistor (e.g., 200 omega/square) the TCR is independent of implant energy. However, for high value resistors (e.g., > 1000 omega/square) the TCR obtained for a resistor of a particular value is directly dependent on the energy level used, i.e., increase in TCR with increase in energy. This effect was found for both boron and phosphorous for all values measured. Very similar results were seen for arsenic resistors with the exception of the 5000 omega/square resistor.

The results in this article can be used to precisely tailor an ion...