High-Performance Poly-Si TFTs of Top-Gate with High-kappa Metal-Gate Combine the Laser Annealed Channel and Glass Substrate

Abstract

We demonstrate high-performance low-temperature poly-Si thin film transistors (LTPS-TFTs) with a TaN/Hf-based top-gate-stack and combine the channel film by laser annealing and glass substrate (glass substrate high-kappa metal-gate thin film transistor, called GSHM-TFTs). The GSHM-TFTs of n-channel (called GSHM-NTFTs) exhibit a very low threshold voltage, low supply voltage (similar to 2 V), steep subthreshold swing (S.S.) similar to 95 mV/dec, and high I(ON)/I(OFF) ratio >10(7). In contrast, GSHM-TFTs of p-channel (called GSHM-PTFTs) exhibit an S.S. similar to 154 mV/dec and an I(ON)/I(OFF) ratio even higher than 10(8). Furthermore, the driving currents are also enhanced in GSHM-TFTs. These significant improvements are due to the combination of laser annealed channel film and the very high gate-capacitance density provided by HfO(2) gate dielectrics with the effective oxide thickness of 14 nm. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3504147] All rights reserved.