Double-metal-gate nanocrystalline Si thin film transistors with flexible threshold voltage controllability

Abstract

We fabricated nano-crystalline Si (nc-Si: H) thin-film transistors (TFTs) with a double-metal-gate structure, which showed a high electron-mobility (mu(FE)) and adjustable threshold voltages (V-th). The nc-Si: H channel and source/drain (S/D) of the multilayered TFT were deposited at 375 degrees C by inductively coupled plasma chemical vapor deposition. The low grain-boundary defect density of the channel layer is responsible for the high mu(FE) of 370 cm(2) /V-s, a steep subthreshold slope of 90 mV/decade, and a low V-th of -0.64 V. When biased with the double-gate driving mode, the device shows a tunable V-th value extending from -1V up to 2.7 V. (C) 2013 AIP Publishing LLC.