Novel concepts for mass storage of archival data

Abstract

Energetic beams of heavy ions are an excellent tool for recording digital information in insulating materials. This ionographic process is based on the introduction of radiation damage up to the amorphisation level in thin layers of insulators, preferentially of elemental semiconductors such as silicon or diamond. Due to the greatly enhanced optical absorption in locally irradiated areas strong optical contrast with reference to the non-damaged crystalline matrix is realised. The generated patterns are sufficiently stable as to guarantee a practically unlimited lifetime. Focused ion beams of heavy rare gases, as generated from a gas-field ion source, constitute an effective pencil for writing pixels of dimensions as small as 10 nm. Thus, by using records of 100 and 10 nm pixel diameter one can store about 1 and 100 Tbit, respectively, on a 100 cm 2 disc. Whereas standard optical reading technology is confined to the upper size limit, near-field technology is required for smaller structures. The feasibilty of recording in some group IV materials will be demonstrated.