Investigation of active Si pitting and its impact on 0.15 and 0.30 μm n-type metal-oxide-semiconductor and p-type metal-oxide-semiconductor transistors

Abstract

The root causes of active pitting in a dual-doped gate MOSFET process were studied. These include the etch chamber configuration, the etch chemistry used, and the etch rate variation due to pattern density and different dopant species in the polysilicon gates. It was observed that pitting can lead to degradation of device characteristics, such as drive current, series resistance, and transconductance.