Channel Width Splitting Effect on Driving Characteristics of Silicide Seed-Induced Laterally Crystallized Poly-Si Thin-Film Transistors

Abstract

The electrical performance of low-temperature polycrystalline silicon thin-film transistors (TFTs) is greatly affected by structures such as channel geometry, lightly doped drain, film thickness, etc. In this paper, the split channel polycrystalline silicon TFTs are fabricated through the silicide seed induced lateral crystallization method by dividing channel width with fixed numerical channel size. The number of channels splitting from 1 to 10 significantly improves driving characteristics such as driving current, field-effect mobility, subthreshold slope, and threshold voltage. It is found that the two main causes of improvements are the enlargement of effective channel width and a decrease in series resistance due to the crystal filtering effect on narrowly split channels, which lead to trap-state density reduction during lateral crystal growth. The causes of enlarged effective channel width and the decreased series resistance by the crystal filtering effect are demonstrated through capacitance-voltage and trap-state density extraction.