Electrical Characteristics of High-Mobility Fine-Grain Poly-Si TFTs from Laser Irradiated Sputter-Deposited Si Film

Abstract

Electrical characteristics of n-channel fine-grain polycrystalline silicon thin-film transistors (poly-Si TFTs) fabricated from a sputter-deposited Si film irradiated with laser light have been measured. The fine-grain poly-Si TFTs have attained a high mobility of 383 cm 2 /V·s despite a small grain size from 40 nm to several hundred nanometers. The high-mobility fine-grain poly-Si TFTs feature decreases in mobility with gate voltage and decreases in drain current with temperature in a manner similar to single-crystal MOSFETs. They also show a low carrier trap state density N st at grain boundaries of 5.6×10 11 cm -2 . High mobility in the poly-Si TFTs is due to a low N st .