We present silicon nitride layers deposited by the hot-wire chemical vapor deposition technique at low substrate temperatures of 300-475 degreesC. We show that materials with a range of compositions from silicon rich to nitrogen rich can be made. Postdeposition oxidation and moisture penetration of layers deposited in a defined parameter regime is studied. Stoichiometric, dense layers with a hydrogen content of approximately 9 at.% were deposited and incorporated in TFTs, with both the silicon and silicon nitride deposited by HWCVD. Good device properties with mobilities of 0.3-0.6 cm(2)/V s were reached.