Investigation of Abnormal Off-Current in p-Channel Double Diffused Drain Metal-Oxide-Semiconductor Transistors after Hot Carrier Stress

Abstract

This paper studies the degradation behaviors in IV characteristics and the corresponding improvement for p-channel double diffused drain metal-oxide-semiconductor (DDDMOS) transistors after hot carrier stress (HCS). There is an apparent current which is flowed from source to drain in the off-region after HCS. According to the IV characteristic comparisons between different device structures and ISE-TCAD simulation results, the location and mechanism of this abnormal off-current can be demonstrated. Furthermore, this off-current is suppressed effectively by the different process flows in STI fabrication for this DDDMOS device.