BURIED-CHANNEL MOSFET MODEL FOR SPICE

A buried-channel (BC) MOSFET model is not currently available in the Berkeley version of SPICE 3. In this paper we present a new BC-MOSFET model for dc, transient and small-signal circuit simulation which we incorporated into SPICE 3B1. Our model includes all of the modes of operation inherent to the BC-MOSFET including the partial modes of operation. Inclusion of these partial modes of operation within the BC-MOSFET charge model distinguishes our model from those proposed to date. In our model the dc characteristics cater to the secondary effects as surface scattering and velocity saturation through the use of mobility models. Further, our treatment of the mobility in the BC-MOSFET model is more thorough. The bulk and surface mobilities are treated as being dependent up to the channel potential and as a result must be evaluated within the integration of the drain current. This results in a more accurate profile of the mobility along the device channel. A number of examples are presented to illustrate our model. These results are compared to experimental measurements and show good agreement.