A compact-charge LDD-MOSFET model

A compact-charge LDD-MOSFET model, based on an analytical surface potential formulation at source and drain has been derived and implemented in the circuit simulator SABER for all channel length and width down to deep submicrometer. Besides well-known short- and narrow-channel effects, the model includes additional charge effects around the threshold voltage as well as a bias dependent charge description of the overlap LDD(S)-region. These additional capacitance effects are not considered in conventional submicrometer transistor models although they domain the capacitance characteristic with further downscaling. If not taken into account, simulation errors of, e.g., up to 50% in the frequency of a 0.3 μm CMOS ring oscillator or over 100% in the 3 dB critical frequency of amplifier circuits can result