Hydrogenated amorphous silicon for archival storage

Changes in optical reflectivity of hydrogenated amorphous silicon films of up to 90% have been induced by Ar laser processing, and are correlated with hydrogen evolution from the material. Accompanying changes greater than three orders of magnitude in resistivity also provide a mechanism for interrogation of the stored data by an electron beam. Storage densities as high as 109 bits/in2 for optical recording and 1011 bits/in2 for recording with electron beams are predicted on the basis of these results.