Thin-film transistors deposited by hot-wire chemical vapor deposition

In the past few years hot-wire chemical vapor deposition (HWCVD) has become a popular technique for the deposition of silicon-based thin-film transistors (TFTs). Several groups have been using hot-wire deposited amorphous and microcrystalline silicon as the active layers in TFTs. In such devices either thermal SiO2 or plasma-deposited silicon nitride was the gate insulator. Recently 'All-Hot-Wire TFTs' have been realized, with also the silicon nitride deposited by HWCVD. This paper reviews the characteristics of hot-wire TFTs with amorphous and microcrystalline silicon using plasma- or hot-wire deposited silicon nitride as the gate insulator. It has been shown that hot-wire TFTs have a higher stability upon gate-bias stress as compared to their plasma-deposited counterparts. We present an overview of the stability of hot-wire TFTs deposited at a range of substrate temperatures. The higher stability of hot-wire TFTs that have been deposited at temperatures of 400-500 degreesC is ascribed to an enhanced structural order, i.e. a higher degree of medium-range order of the silicon network. (C) 2003 Elsevier Science B.V. All rights reserved.