Characteristics of Poly-Si Thin Film Transistors with Highly Biaxially Oriented Linearly Arranged Poly-Si Thin Films Using Double Line Beam Continuous-Wave Laser Lateral Crystallization

摘要

Highly biaxially oriented linearly arranged poly-Si thin films were formed by double-line beam continuous-wave laser lateral crystallization (DLB-CLC). Crystallinities of the poly-Si thin films were (110), (111), and (211) for the laser scan, transverse, and surface directions, respectively, and an energetically stable ∑3 grain boundary was dominantly observed. Silicon grains were elongated along the laser scan direction and one-dimensionally very large silicon grains with lengths of more than 100 μm were formed. High-performance low-temperature poly-Si thin film transistors (TFTs) using these poly-Si thin films were fabricated at low-temperatures (≤550°C) by a metal gate self-aligned process and a TFT with a high electron field effect mobility of μ_(FE)=560 cm~2V~(-1)s~(-1) in a linear region was realized. Also, electron field effect mobility variation of below 10% was obtained at the same crystallization region. Leakage current mechanism was also investigated by temperature dependence of the TFT characteristics.