Optical recording in hydrogenated amorphous silicon

An archival optical storage technique based on hydrogen evolution in hydrogenated amorphous silicon (a-Si:H) is presented. Thin films (∼0.5 μm) of a-Si:H have been prepared by rf glow discharge in SiH4 and deposited on a thermally grown oxide pattern formed on float zone 〈111〉 crystalline Si (c-Si) substrates. Replication of the oxide pattern is achieved by ablation of the a-Si:H layer after annealing. This low-temperature process produces a predesigned array of circular holes caused by bursting of microbubbles in the a-Si:H layer. In comparison, the circular holes nucleate randomly on unoxidized c-Si.