High performance low temperature polycrystalline Si thin-film transistors fabricated by silicide seed-induced lateral crystallization

Abstract

A novel and simple crystallization method for high performance polycrystalline silicon (poly-Si) thin-film transistors (TFTs) using Ni silicide seed-induced lateral crystallization (SILC) was proposed in this study, and it includes no additional deposition and/or etching processes that are not found in the fabrication of conventional metal-induced lateral crystallization (MILC) TFTs. The poly-Si thin films crystallized by SILC were characterized by x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Micro-Raman spectroscopy. The electrical properties were obtained from ID-VG transfer curves and the interface trap density was determined by Levinson plot analysis. The results show that SILC poly-Si films have lower Ni contamination, better crystallinity, and higher crystalline fraction than MILC poly-Si films. The p-channel SILC poly-Si TFTs exhibited a mobility of 66 cm2/V·s, a minimum leakage current of 3.4 × 10−11 A at VD = −5 V, a subthreshold slope of 0.85 V/dec, and a maximum on/off ratio of 5.0 × 106, all of which resulted in a high-performance device which surpassed conventional MILC poly-Si TFTs.