Combinatorial approach to studying tungsten filament ageing in fabricating hydrogenated amorphous silicon using the hot-wire chemical vapour deposition technique

摘要

Tungsten filament ageing is a major concern in the applications of hydrogenated amorphous silicon (a-Si:H) and other thin films deposited by hot-wire chemical vapour deposition (HWCVD). A series of sequentially deposited samples was made on a single substrate using a combinatorial HWCVD system to sample and study the continuous ageing of the filament. The study found that filament ageing is associated with changing surface morphology, sagging and deteriorating electronic properties of the filament. The fact that the deposition rate of a-Si:H decreases with an aged filament is attributed to the decrease of filament temperature. The reaction between silicon and tungsten is the main cause of filament ageing.