Construction of probe-based data storage with ultra-high areal density

Abstract

Our probe-based data storage (PDS) system consists of four parts: signal processing module, multi-probe array, xy-planar actuator, and recording media. The signal-processing module has 2 layers attached to each other. The first layer has 3 D wiring, and it is assembled to the second layer (ASIC module) for the signal processing circuit. The multi-probe array is designed to increase recording and reading speed of the data bits. Each probe has cantilever and tip that are characterized by a tip height of 15 /spl mu/m, a tip radius of 15 nm, a natural frequency of 18.75 kHz and a DC sensitivity of 16.7 nm/V. Poly-silicon probe was fabricated by molding technique to produce high aspect ratio tips. The electrostatic planar actuator serves as a scanner that positions the probe to the right place by moving the media in xy-plane. The moving distance was /spl plusmn/40 /spl mu/m at 10/spl plusmn/10 V, DC gain was 3.04 /spl mu/m/V at 4 V, and the resonance frequency was 143 Hz. The: recording media stores the recorded information in the form of electric polarization in ferroelectric materials. Ferroelectric Pb(Zr,Ti)O/sub 3/ thin film is a candidate material for the media, and it can yield a memory density as high as 400 Gb/in/sup 2/ by recording bits as small as 35 nm in diameter. The bits are fully rewritable and retain the information for a generation at the temperature range below than 50 /spl deg/C.