The Relation Between Degradation Under DC and RF Stress Conditions

Abstract

In this paper, we develop a method to derive degradation formulas for time-varying stress from the formulas for the constant-bias case, discuss its limitations, and apply it to a set of radio-frequency (RF) stress experiments. First, we will give a new derivation of the well-known power-law case without invoking any specific physical degradation model. Next, we will show that this derivation can be generalized to the broader class of degradation functions of type <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i> ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Vi</i> )· <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</i> ). We will illustrate our work with an example of hot-carrier degradation in 45-nm n-channel metal-oxide-semiconductor field-effect transistors, where an accurate prediction of the measured lifetime under RF stress conditions is obtained from the measured degradation under direct-current stress.