  In this paper, we present the unique features exhibited by modified
asymmetrical Double Gate (DG) silicon on insulator (SOI) MOSFET. The proposed
structure is similar to that of the asymmetrical DG SOI MOSFET with the
exception that the front gate consists of two materials. The resulting modified
structure, Dual Material Double Gate (DMDG) SOI MOSFET, exhibits significantly
reduced short channel effects when compared with the DG SOI MOSFET. Short
channel effects in this structure have been studied by developing an analytical
model. The model includes the calculation of the surface potential, electric
field, threshold voltage and drain induced barrier lowering. A model for the
drain current, transconductance, drain conductance and voltage gain is also
discussed. It is seen that short channel effects in this structure are
suppressed because of the perceivable step in the surface potential profile,
which screens the drain potential. We further demonstrate that the proposed
DMDG structure provides a simultaneous increase in the transconductance and a
decrease in the drain conductance when compared with the DG structure. The
results predicted by the model are compared with those obtained by
two-dimensional simulation to verify the accuracy of the proposed analytical
model.
