Empirical model of MOSFET breakdown voltages

An additive model of drain-to-source current of a MOS transistor in the breakdown region is presented for the circuit-simulation SPICE program. An additional drain-to-source current is described by mixed quadratic and exponential formulas. Continuity of current and its first derivatives is assured. This guarantees a convergence of the Newton-Raphson algorithm used in SPICE. Variation of the drain-to-source breakdown voltage at V/sub gs/=0 and of the injection-induced breakdown voltage at V/sub gs/>V/sub th/ with the gate-to-source voltage and the effective channel length is taken into account. Most of the model parameters have physical meanings and they are easily measurable.>