High Electron Mobility TFTs of Nanocrystalline Silicon Deposited at 150°oC on Plastic Foil

Abstract

ABSTRACTTop gate n-channel thin film transistors (TFTs) of nanocrystalline silicon (nc-Si:H) were fabricated on Kapton polyimide film substrates at a maximum process temperature of 15°C. These are thefirst nc-Si:H TFTs ever made on a plastic substrate. Both intrinsic and n+ source/drain layers were directly deposited at 80 MHz excitation frequency for high growth rate. Coplanar TFTs with top source/drains and staggered TFTs with bottom source/drains were made. The coplanar top gate and top source/drain structures have linear electron mobility of ∼ 30 cm2V-1s-1 and ON/OFF ratio up to ∼ 105. TFTs with the top gate and bottom source/drain structure made to date have linear mobility of up to ∼ 12 cm2V-1s-1 and ON/OFF ratio of ∼105.