Convergence of Hot-Carrier-Induced Saturation Region Drain Current and On-Resistance Degradation in Drain Extended MOS Transistors

Hot-carrier-induced device degradation in n-type high-voltage drain-extended MOS (DEMOS) devices stressed under high drain voltage and high gate voltage (Vg) is investigated. Charge pumping data and technology computer-aided-design simulation results reveal that hot-carrier-induced interface state formation in the gate overlapped shallow trench isolation region is responsible for device degradation. Furthermore, an unexpected high saturation region drain current (Id(sat)) degradation (close to on-resistance degradation) is observed. The occurrence of quasi-saturation under high Vg bias is the cause of significant Id(sat) degradation. The results presented in this paper suggest that severe Id(sat) degradation may become a reliability concern for devices exhibiting the quasi-saturation phenomenon.