A nonoptical shear-force method for tip-sample distance regulation

A simple, compact and inexpensive non-optical method for maintaining a constant separation between a fixed sample and probe based on a single dither-detection piezoelectric slice is presented. The covering piezoceramic with electrodes of a thin cantilever, which produced from the piezoelectric slice of a miniature buzzer, is cut into 2 pads. One pad is for excitation and the other pad is for detection. The sharpen fiber is mounted on the surface of the detection pad, an ac voltage is applied to driving the cantilever at the combined fiber-cantilever resonance frequency. As the probe approaches the sample surf ace, "shear force" effectively damps its vibrational amplitude. This effect can be used to regulate probe-sample separation. Using this single dither-detection piezoelectric slice, we have obtained the topography of an 8 μm × 8 μm area of a CD. We expect that this technique will find application not only in the field of scanning force microscopy but also in Near-field Optical Microscopy as a means to maintain constant probe-sample separation.