Analysis of static and dynamic performance of short-channel double-gate silicon-on-insulator metal-oxide-semiconductor field-effect transistors for improved cutoff frequency

A comprehensive analysis of the static and dynamic characteristics of deep submicron double-gate (DG) and single-gate (SG) silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) is presented, based on two-dimensional (2D) numerical simulations for high-frequency analog applications. Results from the static analysis show that a DG MOSFET offers excellent performance with respect to short-channel immunity, drain current enhancement and improvement in transconductance, Early voltage and voltage gain. We also analyze the impact of volume inversion (VI) on the performance of DG devices under saturation conditions, and investigate, in detail, the level of current enhancement and the bias conditions under which it can be achieved. Results show that a current as high as 15 times that of single-gate (SG) MOSFETs can be achieved in DG devices at a transconductance-to-current ratio of 25 V-1. Analysis of the dynamic part shows that due to the dual-gate structure, DG devices offer nearly twice the gate-source capacitance as compared to SG devices, thus limiting the cutoff frequency at higher gate voltages and longer channel lengths. At shorter channel lengths (L <= 50nm) and low gate overdrive voltages (<400mV), DG devices show a significant improvement in cutoff frequency compared to SG devices, thus making double-gate SOI MOSFETs potential candidates for high-frequency analog applications.