Analysis of the Threshold Voltage BSIM-Model for a Short Channel PD-SOI DTMOS

The threshold voltage is a fundamental parameter necessary to predict the correct behavior of circuits based on Dynamic Threshold MOSFETs. In this work, we analyzed the short channel effects on this parameter. PISCES simulations of short and long channel MOSFET´s based on a 0.2 mum PD-SOI technology were used to investigate the validity of the BSIMSOI model under substrate forward bias. The simulation results showed that the dependence of the threshold voltage on the substrate forward bias can differ importantly from the BSIMSOI model for short channel devices, but it could agree with BSIMSOI model for long channel devices. Under substrate forward bias, an improved definition for the minimum surface potential must be used in order to eliminate the differences between the BSIMSOI model and PISCES simulations for short channel devices.