Simulation of Carbon Nanotube Field Effect Transistor with Two Different Gate Insulator

Abstract

In this paper, a novel structure for MOSFET like CNTFETs (MOSCNTs) is proposed, combining the advantages of both high and low dielectrics to improve output characteristics. In this structure, the gate dielectric at the drain side is selected from a material with low dielectric constant to form smaller capacitances while a material with high dielectric constant is selected at the source side to improve on current and reduce leakage current. The new structure is simulated based on Schrödinger-Poisson formulation. Obtained results show that the proposed configuration has lower off and higher on current in comparison with low-k MOSCNTs. Also, using a two-dimensional model, a wide range of the new structure performance parameters is studied. It is found that transconductance, intrinsic cut-off frequency and quantum capacitance parameters are improved compared to MOSCNTs with low dielectric constant. It is clear that the proposed structure can provide DIBL and subthreshold swing near its theoretical limit while it also profits from smaller capacitances in gate, drain and source in comparison with high-k MOSCNTs.