Modelling the effects of dielectric materials and body bias on the transconductance in N-channel MOSFETs

This research investigates the effect of various dielectric materials on gate terminals of n-channel Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). As MOSFETs play a key role in modern electronics, this research investigates the performance of n-channel MOSFETs for different dielectric materials. The dielectric in MOSFETs isolates the gate polysilicon electrode from the semiconductor channel, controlling the flow of current through the device. Silicon dioxide (SiO2) has historically been the dielectric of choice due to its excellent insulating properties and compatibility with silicon technology. However, there is significant demand for enhanced MOSFET performance. Hence, dielectrics with higher dielectric constants have gained more prominence. This research makes use of SiO2, HfO2, BaTiO3, and ZnO as dielectric materials to evaluate the transfer characteristics of n-channel MOSFETs. It was found from the transfer characteristics that HfO2 exhibited the highest transconductance of 0.8 μA/V as compared to 0.1528 μA/V, 0.108 μA/V and 0.00057 μA/V for BaTiO3, SiO2, and ZnO dielectrics, respectively. In addition, the body bias effect was investigated for n-channel MOSFET with SiO2 as dielectric layer. It was observed that as the body bias voltage varied as 0, 0.25, 0.5 and 0.6 V, the transconductance decreased as 0.3778, 0.2145, 0.1346 and 0.0724, respectively. Our findings demonstrate the benefits of increased transconductance in applications such as analog to digital converters and switching power supplies (DC to DC converters), since precise signal conversion and quicker switching speeds are made possible by increased transconductance.