Analysis of interface charge for ultra-thin Al₂O₃ gate dielectric based MOS devices using capacitance-voltage method

In this paper, the Flatband voltage (Vfb) is calculated in terms of interface trap charges (Qit), fixed oxide charges and oxide trapped charges for ultra-thin oxide Metal Oxide Semiconductor (MOS) Devices using SiO2 and Al2O3 materials. The interface charges are calculated 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 × 10¹⁷cm⁻³. Numerical calculations and Analytical solutions are performed by MATLAB and device simulation was done using ATLAS, a commercially available TCAD tool from SILVACO and excellent agreement was observed over a wide range of oxide thickness for the materials.