Miniaturized Single-Crystal Silicon Cantilevers for Scanning Force Microscopy

We report on a method to reproducibly batch-fabricate single-crystal silicon cantilevers with dimensions an order of magnitude smaller than conventional cantilevers, i.e. , with lengths between 10 and 35 um, a width of 4 um, and a thickness of 0.2 um. The cantilevers are attached to support chips specially tailored for use in a scanning force microscope. The resonance frequencies are 0.2-2 MHz, the spring constants about 0.05-1 N/m, and the quality factors 1.5-3.0 times 10**4. The resulting thermal force noise is 1-2 times 10**(-16) N/Hz**(1/2) at room temperature in vacuum. These cantilevers allow an enhancement of the measurement speed of more than one order of magnitude, and 2 to 5 times better force sensitivity. After annealing in ultra-high vacuum and measuring at liquid helium temperature, the thermal force noise of these cantilevers is expected to be further reduced down to 10**(-18) N/Hz**(1/2).