Performance of MOS Capacitor with Different Dielectric Material Simulated Using Silvaco TCAD Tools

Abstract

Metal oxide semiconductor (MOS) capacitor is a trilayer device that comprises of metal, dielectric, and semiconductor layer. The advancement of MOS technology has greatly give huge improvement to MOS devices which lead to scaling down the MOS devices. The reduction of dielectric thickness of conventional dielectric material has coming to an end, therefore as alternative new material with high mobility carrier is suggested to overcome the problem. The objectives of this work are to study the performance of MOS capacitor. Two parameters were varied, first the semiconductor material which is silicon (Si), germanium (Ge) and silicon germanium (SiGe) and second is the dielectric material that is silicon dioxide (SiO2) and silicon nitride (Si3N4). The performance of the MOS capacitor is evaluated based on the capacitance-voltage (C-V) and current-voltage (I-V) characteristics. Silvaco TCAD tool were use as as simulation tool for the method of investigation. Result shown that the performance of the MOS capacitor increased when Ge and SiGe were used as semiconductor material and Si3N4 as dielectric layer. It can see that with VT of 4.15 V for MOS with Ge and 4.28 V for MOS with SiGe. For the C-V properties Cmax value for both devices are F and F, respectively. The results show that there is around 100% increment in capacitance value when Ge is used as semiconductor layer but there is no increment or decrement in capacitance value when SiGe is used. Based on the obtained results, Ge is chosen as the best semiconductor material.