Hot wire chemical vapor deposition of Si containing materials for solar cells

A review of the hot wire chemical vapor deposition (HWCVD) of Si-containing materials for solar cell applications is given. A short history of the technique is given, starting from the early 1970s up to the present time. This is followed by a summary of radical detection and gas phase interaction results aimed towards achieving a basic understanding of this process. Next, issues particular to HWCVD growth are presented. These deal mainly with the filament, and include different methods of mounting filaments, filament contamination issues, filament alloying and its effect on both filament lifetime and film properties, and substrate heating by the filament. Differences between PECVD and HWCVD growth are then summarized, and this is followed by examples of research results indicating unique film properties. Included in these examples are works on amorphous silicon, microcrystalline silicon, silicon nitride, and a new technique for deposition of large grained poly Si by utilizing the etching of silicon by atomic hydrogen produced by the filament. Finally, the future prospects of HWCVD are briefly discussed.