Performance Comparison of Interdigitated Thin-Film Field-Effect Transistors Using Different Purity Semiconducting Carbon Nanotubes

Abstract

In this paper, we present the fabrication and characterization of semiconducting carbon nanotube thin-film field-effect transistors (SN-TFTs). High-k dielectric material, hafnium-oxide (HfOX) is used as the gate-oxide of the device. A Thin-film of semi-conducting single walled carbon nanotube (SWCNT) is deposited on the amino-silane modified HfOX surface. Two types of SN-TFTs with interdigitated source and drain contacts are fabricated using 90% and 95% purity of semiconducting SWCNTs (s-SWCNT), have exhibited a p-type behavior with a distinct linear and saturation region of operation. For 20 µm channel length SN-TFT with 95% pure s-SWCNTs has a peak on-off current ratio of 3.5×104 and exhibited a transconductance of 950 µS. The SN-TFT fabricated with HfOX gate oxide has shown a steep sub-threshold slope of 750 mV/decade and threshold voltage of -0.7 V. The SN-TFT of channel length 50 µm has exhibited a maximum mobility of 26.9 cm2/V•s.