High-density data storage using proximal probe techniques

Abstract

We describe some of the achievements and problems associated with proximal probe-based approaches to high-density data storage. While STM-based methods have demonstrated spectacular areal densities dwarfing anything achievable with today's storage technologies, reliability and data rate issues present serious obstacles. These problems have led us to focus on techniques based on AFM and near-field optics. First, we have developed a thermomechanical writing scheme using an AFM tip. We have addressed many of the practical issues involved, including data rate. With custom low-mass cantilevers, we have demonstrated readback on real data with a data rate of 1.2 Mb/s. We have also pursued nontopographic storage techniques based on charge storage in nitride-oxide semiconductor structures and near-field optical storage. These techniques should be able to achieve densities comparable to those reached with the AFM scheme, with the added advantage that they are fast and reversible. Although it is not yet clear whether any of these probe-based approaches can ever be made practical, they do represent potential pathways to the higher densities that will be needed in the decades ahead.