Implantation Temperature Effects on the Nanoscale Optical Pattern Fabrication in a-SiC:H Films by Ga~+ Focused Ion Beams

摘要

This work is related to a novel approach of providing some new generation ultrastable (＞50 years), ultrahigh density (＞1 Tbit/sq.in.) data storage for archival applications. We used ion-implantation to write nanoscale data into hydrogenated amorphous silicon carbide (a-SiC:H) films. Wide bandgap a-SiC:H samples, Ga~+ focused ion beam implanted, have been prepared. A range of samples has been focused ion beam patterned under different implantation conditions, with emphasis on different substrate temperatures (typically from 0℃ temperature to around room temperature). Some of the room temperature implanted samples were further annealed at +250℃ in vacuum. The focused ion beam patterned samples were then analysed using near-field techniques, like atomic force microscopy, to define optimum implantation conditions and the resulting consequences for archival data storage applications. The atomic force microscopy analysis of Ga~+ focused ion beam implanted a-Si_(1-x)C_x:H samples at room temperature and at 0℃ revealed an increase of both the depth and the width of the individual lines within the focused ion beam written patterns at the lower temperature, as a result of an increased ion beam induced sputtering yield, in good agreement with the previous results for the case of Ga~+ broad beam implantation in a-Si_(1-x)Co_x:H and again suggesting that the best conditions for optical data storage for archival storage applications would be using Ga~+ ion implantation in a-SiC:H films with an optimal dose at room temperatures. Similarly, the atomic force microscopy results confirm that no advantage is expected to result from post-implantation annealing treatments.