Electrical characteristics and optimization of extended-drain MOS transistor with dual-workfunction-gate for mixed-signal applications

摘要

This paper presents the electrical characteristics of high-voltage (HV) extended-drain MOS (EDMOS) field-effect transistor with dual-workfunction-gate (DWFG) to enhance the device performance and device optimization for mixed-signal applications. For n-channel DWFG EDMOS device fabrication, the polycrystalline-silicon (poly-Si) gate on the source and drain side were doped by p+ and n+ ion implantation, respectively. The DWFG device with shorter p+ poly-Si gate length showed lower on-resistance (R_(ON)) characteristics compared to the conventional device. Therefore, the DWFG device with shorter p+ poly-Si gate length is suitable for switching applications. On the other hand, the best improvements in the drain conductance (g_(ds)) and intrinsic voltage gain (A_V), which is important parameters of analog circuits, were shown in the DWFG device with identical n+ and p+ poly-Si gate length.