Fabrication and characterization of novel semiconductor nanomechanical structures

As an application of the "bottom-up" self-organization growth technique to the fabrication of nanoscale mechanical structures, we selectively etched a GaAs sacrificial layer under InAs wires preferentially grown on bunched steps on misoriented GaAs(110) surfaces, which led to the successful formation of single crystal InAs nanoscale cantilevers. The lengths, widths, and thicknesses of the nanolevers are typically 50-300, 20-100 and 10-20 nm, respectively. The force constant, as measured by the force-modulation imaging technique using contact-mode atomic force microscopy, ranges from 0.5 to 10 N/m, showing good agreement with that estimated from the elastic constant of InAs. The resonance frequency is expected to reach 500 MHz for the smallest one, which promises possible application to high-speed nanomechanical devices.