Mixed-Signal Performance of Various High-Voltage Drain-Extended MOS Devices

Abstract

In this paper, the optimization issues of various drain-extended devices are discussed for input/output applications. The mixed-signal performance, impact of process variations, and gate oxide reliability of these devices are compared. Lightly doped drain MOS (LDDMOS) was found to have a moderate performance advantage as compared to shallow trench isolation (STI) and non-STI drain-extended MOS (DeMOS) devices. Non-STI DeMOS devices have improved circuit performance but suffer from the worst gate oxide reliability. Incorporating an STI region underneath the gate-drain overlap improves the gate oxide reliability, although it degrades the mixed-signal characteristics of the device. The single-halo nature of DeMOS devices has been shown to be effective in suppressing the short-channel effects.