Investigation of abnormal off-current in p-channel double diffused drain metal-oxide-semiconductor transistors after hot carrier stress

摘要

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.