Analysis of Interface Charge Using Capacitance-Voltage Method for Ultra Thin HfO2 Gate Dielectric Based MOS Devices

摘要

In this paper, we have calculated Flatband voltage (V fb ) in terms of interface trap charges, fixed oxide charges and oxide trapped charges for ultra thin oxide Metal Oxide Semiconductor (MOS) Devices using SiO 2 and HfO 2 has been methodically investigated. The interface charges are designed using capacitance-voltage (C-V) method. It indicates that by reducing the oxide thickness, the interface charges increases linearly. It is originated to be in good agreement with ATLAS simulation results at p-type doping level of 1 × 10 17 cm -3 . It has been evaluated that with respect to SiO 2 for the same oxide thickness, HfO 2 contributes less to V fb . Numerical calculations and Analytical solutions are performed by MATLAB and we simulate the capacitance-voltage (C-V) characteristics of the MOS devices with ultrathin oxide using ATLAS, a commercially available TCAD tool from SILVACO. The tool has investigated the effect on C-V characteristics of different oxide thickness of SiO 2 and HfO 2 . Excellent agreement was observed over a wide range of oxide thickness for the materials.