A new method to monitor gate-oxide reliability degradation

Abstract

Recently, a new method which uses the initial electron trapping rate (IETR) of the gate-oxide to detect plasma damage was introduced. In this paper, the transistor hot-carrier life-time (HCLT) degradation due to plasma damage is shown to be related to the IETR, and thus establishes a new way to monitor gate-oxide reliability. The IETR is directly proportional to the pre-existing electron-trap density. Thus hot-carrier degradation in plasma damaged gate-oxide is by electron trapping instead of by interface-state generation normally expected for n-channel transistors. In addition, post Fowler-Norhein (FN) stress transistor parameter variation due to plasma damage is also shown to be linear to the IETR. A relationship between the hot-carrier stress method and the FN stress method for plasma induced latent damage measurement is thus established.