Dynamic stressing of thin oxides

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, QBD, and the total stressed time-to-breakdown, tBD, 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 QBDand tBDof dynamic stressing are greater than those of DC stressing. For 0.1 ms pulses, QBDand tBDare about four times larger than what DC stressing would predict. The main reason for the higher QBDand tBDunder 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 QBDfor dynamic stressing.