This paper reports about low-temperature nitridation of silicon surfaces using ammonia decomposed species generated on a heated tungsten filament. The surface of Si(100) was nitrided at low temperatures as low as 50 degrees C. The relation between nitridation time and nitridation layer thickness showed that the layer thickness follows the linear law for small nitridation time and a parabolic relationship for large time. The water contact angle measurements revealed that nitridation layer proceeds with island growth in the early stage of nitridation. (c) 2005 Elsevier B.V. All rights reserved.