Towards an All-Hot-Wire TFT: Silicon Nitride and amorphous Silicon deposited by Hot-Wire Chemical Vapor Deposition

Abstract

ABSTRACTWe present thin-film transistors with both amorphous silicon and silicon nitride deposited by hot-wire chemical vapor deposition. Hot-wire amorphous silicon with good electrical properties was deposited from the decomposition of silane at a substrate temperature of 250°C. For Hot-wire silicon nitride we used silane and ammonia at a substrate temperature of 340°C. In this paper we address structural and electrical properties of this material. A high ammonia flow results in porous films that exhibit post-deposition oxidation. By limiting the ammonia/silane ratio to 30, compact layers with a hydrogen content of only 10 at.% and a refractive index of 1.95 are obtained. Using this layer as gate dielectric results in thin-film transistors with good switching behavior and a field-effect mobility of 0.3 cm2/Vs.