High deposition rate and efficient gas usage are important advantages of Hot Wire Chemical Vapor Deposition (HWCVD). However, the high atomic hydrogen fluxes and high substrate temperature that are involved with the deposition of a-Si and Pc-Si i-layers by this technique are generally disadvantageous for the earlier deposited layers and TCOs. To prevent this, we developed doped layers that show high stability against these extreme i-layer deposition conditions. In n-i-p solar cells with an a-Si absorber layer deposited at high rate (16 angstrom/s) and high substrate temperature (430 degrees C), best efficiencies were obtained with a mu c-Si n-layer deposited by a layer-by-layer process using very high frequency plasma enhanced chemical vapor deposition at high Substrate temperature. (c) 2005 Elsevier B.V. All rights reserved.