Electrical Characteristics of High Performance SPC and MILC p-Channel LTPS-TFT with High-κ 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 (μ FE ~ 114 and 215 cm 2 /V s), ultralow subthreshold swing (SS ~145 and 107 mV/decade), and low threshold voltage (V th ~ -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 ―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.