Dynamic stressing of thin oxides

Abstract

The breakdown of thin oxides due to DC stressing and uni-polarity and bi-polarity dynamic stressing has been compared. For dynamic stressing, the total integrated charge-to-breakdown, Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> , and the total stressed time-to-breakdown, t <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> , depend on both the pulse width and duty cycle of the stressing voltage. Uni-polarity and bipolarity stressing produce similar results. In all cases, both Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> and t <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> of dynamic stressing are greater than those of DC stressing. For 0.1 ms pulses, Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> and t <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> are about four times larger than what DC stressing would predict. The main reason for the higher Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> and t <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> under dynamic stressing is reduced hole trapping at localized weak oxide areas. A transient hole generation and relaxation model is proposed to quantitatively explain the increase in Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> for dynamic stressing.