VLSI-NEMS chip for AFM data storage

Abstract

We report the microfabrication of a 32×32 (1024) 2D cantilever array chip and its electrical testing. It has been designed for ultrahigh-density, high-speed data storage applications using thermomechanical writing and thermal readout in thin polymer film storage media. The fabricated chip is the first VLSI-NEMS (NanoEMS) for nanotechnological applications. For electrical and thermal stability, the levers are made of silicon and the heater/sensor element is defined as a lower doped platform with the tip on top. Freestanding cantilevers are obtained with surface micromachining techniques, which result in better mechanical stability and heatsinking of the chip than with bulk micromachining releasing techniques. Two wiring levels interconnect the cantilevers for a time-multiplexed row/column addressing scheme. Two different versions for the array interconnections have been implemented, one with an additional Schottky diode in series with the lever to reduce crosstalk between levers, and one without diodes to investigate various addressing schemes.