A novel N-MOSFET with air gaps in gate insulator for deep submicron applications

In this paper, a novel MOSFET with two air gaps in gate insulator (AG-MOSFET) is introduced, and it´s AC characteristics, channel electric field, and mobility are analyzed by 2D numerical simulation. The simulated results show higher electron mobility and lower channel electric field under the air gap parts. 26% decrease in gate-drain (C_gd) and gate-substrate (C_gs) capacitances of AG-MOSFET structure is achieved in comparison with conventional MOSFET (C-MOSFET) structure. Also lower gate capacitance (C_g) and higher cut-off frequency is achieved for the AG-MOSFET structure. Cut-off frequency of the AG-MOSFET structure is 0.758 GHz, while it is 0.316 GHz in the C-MOSFET structure at 0 dB.