Physical DC models of lateral high-voltage SOI MOSFETs including the self-heating effects

We have developed two models of lateral high-voltage silicon-on-insulation metla-on-silicon field-effect transistors (SOI MOSFETs): an isothermal drain current model without the self-heating effect and a non-isothermal circuit model with the self-heating effect. The isothermal drain current model consists of an equation for the channel region and four equations for the drift region which are based on the carrier distribution. In the non-isothermal model, the SOI layer is modeled as a simple thermal network, which is composed of lumped heat capacitors, lumped thermal conductors, and lumped heat sources. The thermal network model is combined with the isothermal drain current model to form the non-isothermal model. The simulation results based on the non-isothermal circuit model reveal a negative differential resistance in the I-V characteristics when a high voltage is applied to the gate of lateral high-voltage SOI MOSFETs for a long duration. The simulation results also show good agreement with the measured I-V characteristics of devices for a wide range of gate pulse durations.