100-nm channel length a-Si:H vertical thin film transistors

This paper reports on hydrogenated amorphous silicon (a-Si:H) vertical thin film transistors (VTFTs) with channel length of 100 nm, using conventional planar TFT processing technology. The device has a fully self-aligned. vertical channel structure, which is highly insensitive to the non-uniformity of reactive ion etching (RIE). Therefore, the VTFT process is very suitable for large-area electronics. Presently, we can demonstrate VTFTs with remarkable ON/OFF current ratio of more than 10(8), low leakage current down to 1 fA, and good subthreshold slope of 0.8 V/dec at V-d = 1.5 V. The impacts of contemporary device issues, such as short-channel effects and contact resistance, on the performance of short-channel VTFTs and suggested avenues for improvement are discussed.