Characteristics of Pr2O3 gate dielectric thin-film transistors fabricated on fluorine-ion-implanted polysilicon films

Abstract

A simple and effective scheme for fabricating high dielectric constant (high-kappa) praseodymium oxide (Pr2O3) gate dielectric thin-film transistors (Pr2O3 TFT) on fluorine-ion-implanted polysilicon films was proposed and demonstrated for the first time. Incorporating the fluorine-incorporation method with high-kappa Pr2O3 gate dielectric cannot only effectively passivate the trap states in the poly-Si film but also significantly increase the gate capacitance density. With the incorporation of fluorine ions, the electrical characteristics of Pr2O3 TFT can be remarkably improved, including smaller threshold voltage, steeper subthreshold swing, higher field-effect mobility, lower gate-induced drain leakage current, and better on/off current ratio. In addition, the incorporation of fluorine ions in the poly-Si film also improves the reliability of Pr2O3 TFT against hot-carrier stress, which is attributed to the formation of stronger Si-F bonds. Therefore, the proposed scheme is a promising technology for high-performance solid-phase crystallized poly-Si TFTs. (c) 2007 The Electrochemical Society. All rights reserved.