3C-Silicon Carbide Nanowire FET: An Experimental and Theoretical Approach

Experimental and simulated I-V characteristics of silicon carbide (SiC) nanowire-based field-effect transistors (NWFETs) are presented. SiC NWs were fabricated by using the vapor-liquid-solid mechanism in a chemical vapor deposition system. The diameter of fabricated SiC NWs varied from 60 up to 100 nm while they were some micrometers long. Their I-V characteristics were simulated with SILVACO software, and special attention was paid to explore the role of NW doping level and NW/dielectric interface quality. The fabricated SiC-based NWFETs exhibit a mediocre gating effect and were not switched-off by varying the gate voltage. Based on the simulations, this is a result of the high unintentional doping (estimated at 1times10¹⁹ cm^-3) and the poor NW/dielectric interface quality. Moreover, a homemade algorithm was used to investigate the ideal properties of SiC-based NWFETs in ballistic transport regime, with NW lengths of 5-15 nm and a constant diameter of 4 nm for which the carrier transport is fully controlled by quantum effects. This algorithm self-consistently solves the Poisson equation with the quantum nonequilibrium Green function formalism. In the ballistic regime, devices with undoped SiC NWs exhibit superior theoretical performances (transconductance: ~43.2times10^-6 A/V and I_ON/I_OFF=1.6times10⁵ for a device with 9-nm NW length) based on their simulated characteristics.