Electrical Characteristics of High Performance SPC and MILC p-Channel LTPS-TFT with High-kappa Gate Dielectric

Abstract

In this article, high performance p-channel, low temperature polysilicon thin-film transistors (LTPS-TFTs) are fabricated by using HfO(2) gate dielectric and two crystallization methods, solid phase crystallization (SPC) and metal-induced lateral crystallization (MILC) are compared. High field-effect mobility mu(FE) 114 and 215 cm(2)/V s), ultralow subthreshold swing (SS similar to 145 and 107 mV/decade), and low threshold voltage (V(th) similar to -1.05 and -0.75 V) are derived from SPC- and MILC-TFTs with HfO(2) gate dielectric, respectively. These excellent electrical characteristics are due to low trap states and much higher gate capacitance density with equivalent oxide thickness similar to 12.3 nm, resulting in lower operation voltage within 2 V of LTPS-TFT without any passivation method. The comparison of SPC and MILC p-channel LTPS-TFTs with HfO(2) gate dielectric is demonstrated. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3177277] All rights reserved.