Ail update and present status of hot wire CVD (HWCVD) in the area of silicon (Si) related materials deposition is given. By comparing research presentation topics for the last two MWCVD Conferences, trends are pointed Out as to the present research directions in Si related research. Such trends include increasing research efforts in microcrystalline-Si (pc-Si), both from materials and a solar cell device standpoint, and also in silicon nitride. At the same time, the number of presentations in devices aside from solar cells has declined, particularly in the area of thin film transistors. The latter is traced to the maturity of this research area using HWCVD. Additional observations are the number of significant research results obtained using lower filament temperatures, the increased use of 'exotic' sources to deposit Si based alloys, and the large number of new research groups joining the HWCVD community, as ail active or collaborative participant. Finally, research areas resulting in materials deposition and/or device fabrication where results are unique to HWCVD are highlighted. (c) 2005 Published by Elsevier B.V.