Browse Prior Art Database

Process for Radiation Hardening of Igfets

IP.com Disclosure Number: IPCOM000046320D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Merz, CJ: AUTHOR [+2]

Abstract

This publication describes a method for rad hardening of insulated gate field-effect transistors (IGFETs) in a post fabrication process and for establishing thresholds of such devices different than the design value, if desired.

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Process for Radiation Hardening of Igfets

This publication describes a method for rad hardening of insulated gate field- effect transistors (IGFETs) in a post fabrication process and for establishing thresholds of such devices different than the design value, if desired.

During radiation damaging of IGFETs employing the radiation present in an E-beam metal evaporation of Al, Ka X-rays and secondaries, the following has been discovered:

.IN 5 1. In thin gate insulator structures positive charge generation levels saturate at about 1700 - 200 mV equivalent threshold voltage after exposure to about 5xl05-l06 rads and show little additional trap generation when exposure levels are increased to the l07-5xl07 rads Si range.

.IN 5 2. After exposure to the 5x105-106 damage level, negative charge starts to generate. This onset of negative charge causes the threshold, which had decreased by some 1.7 V during the initial damaging, to begin to increase. The threshold can be increased to values less than, equal to or greater than the original undamaged value.

This process, which may be termed "Electrical Titration", does not involve the neutralization of the existing positive charge by negative charge since the positive charge level, as detemined by hot electron injection, remains constant. Thus, in this Electrical Titration region, we can say that negative charge generation levels exceed positive charge generation levels and that the generation rate - annihilation rate of pos...