A Study of the non-Weibull distribution of HK PMOS TDDB

Abstract

In DRAM manufacturing, HK dielectric stacks with HfO2/HfSiOx are being used as a replacement for conventional silicon oxide dielectrics for high speed. One of the major problems is reliability of gate dielectric. Especially, non-Weibull distribution in PMOS TDDB has been observed. This abnormal behavior has been attributed to the effect of HKMG bi-layer structure and the Tinv variation. Finally, we suggest precise method for lifetime extraction in this abnormal case.