Quantization effect in Capacitance Behavior of Nanoscale Si MuGFETs

An unusual bump in the gate capacitance characteristics of Si nanoscale MuGFETs is presented and explained here through 3D NEGF quantum simulations. As higher order subbands are populated when the gate voltage is increased, the channel moves closer to the surface. This increases the slope in the Id-Vg and creates the bump in the Cg(Vg) curve as the centroid of the charge moves closer to the Si/SiO2 interface and the capacitance is increased.