Model quality needs to be job one circuit CAD

摘要

A SPICE model is a tool for circuit designers to design their chip. As the design activity shifts from purely digital to increasingly analog/RF applications, an accurate model with smooth device characteristics becomes essential. BSIM3 gains popularity because of its capability to meet these challenges. As CMOS processing evolves and various tunneling/leakage currents begin to surface, companies are exploring BSIM4 for their immediate future use. Regardless of which model is selected, the entire QA flow must be executed before a model is released to the design community. The four essential steps are to ensure 1) there is no kink in the conductance and capacitance calculated in the model; 2) the process specifications are reflected in the model; 3) the trend of various parameters make sense as a function of channel width, length, and device temperature; and finally, 4) the figure of merit from simulating the benchmark circuit is consistent with previous models.