Fabrication of high frequency two-dimensional nanoactuators for scanned probe devices

The authors have developed an integrated silicon process that uses suspended single crystal silicon (SCS) structures to fabricate x-y capacitive translators and high aspect ratio conical tips for scanned probe devices. The integrated nanomechanical device design and the process sequence include methods to form integrated tunneling tip pairs and to produce electrical isolation, contacts, and conductors. Each device occupies a nominal area of 40 μm×40 μm. These devices include a novel self-aligned tip-above-a-tip tunneling structure and capacitive x-y translators defined by electron beam lithography and the thermal oxidation of silicon. The x-y translators produce a maximum x-y displacement of ±200 nm for an applied voltage of 55 V. The low mass (2×10^-13 kg), rigid structure has a measured fundamental mechanical resonant frequency of 5 MHz