Abstract: An accurate model for high-voltage hexagon VDMOST is derived based on a three-dimensional structure and implemented with SPICE.Drift region resistance, buried layer resistance, interior node voltage and variation of internal capacitance with external applied voltage are analyzed in detailed.A DC equivalent circuit model is also proposed, which includes a level 3 NMOS transistor, a controlled source and capacitance, etc.It also accounts for the quasi-saturation effect in high voltage device.This simple model with a clear physical concept also provides easy extraction of inter-electrode capacitances.The I-V simulation results are in good agreement with experimented results with the DC error approaching 5%within the entire voltage range, which can be used in practical applications.

Key words: HVIC, high-voltage VDMOST, model, drift region, equivalent circuit