Understanding MOSFET Models

The selection of the MOSFET model type for use in analysis usually depends on the electrical parameters critical to the application. LEVEL 1 models are most often used for simulation of large digital circuits where detailed analog models are not needed. LEVEL 1 models offer low simulation time and a relatively high level of accuracy with regard to timing calculations. When precision is required, as for analog data acquisition circuitry, use the more detailed models, such as the LEVEL 6 IDS model or one of the BSIM models (LEVEL 13, 39, or 49).

For precision modeling of integrated circuits, the BSIM models consider the variation of model parameters as a function of sensitivity of the geometric parameters. The BSIM models also reference a MOS charge conservation model for precision modeling of MOS capacitor effects.

Use the SOSFET model (LEVEL 27) to model silicon-on-sapphire MOS devices. You can include photocurrent effects at this level.

Use LEVELs 5 and LEVEL 38 for depletion MOS devices.

LEVEL 2 models consider bulk charge effects on current. LEVEL 3 models require less simulation time and provides as much accuracy as LEVEL 2 and have a greater tendency to converge. LEVEL 6 models are compatible with models originally developed with ASPEC. Use LEVEL 6 models to model ion-implanted devices.