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

In this paper, we have calculated Flatband voltage (Vfb) in terms of interface trap charges, fixed oxide charges and oxide trapped charges for ultra thin oxide Metal Oxide Semiconductor (MOS) Devices using SiO2 and HfO2 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 × 1017 cm-3. It has been evaluated that with respect to SiO2 for the same oxide thickness, HfO2 contributes less to Vfb. 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 SiO2 and HfO2. Excellent agreement was observed over a wide range of oxide thickness for the materials.