SCANNING SHEARING-STRESS MICROSCOPE

A new scanning probe microscope based on a scanning tunneling microsco pe (STM) and a frequency shift of an AT cut quartz resonator has been developed. The quartz resonator coupled to a STM sample is oscillated at its resonance frequency. The shift of the resonance frequency corre sponds to the strength of the shearing stress in the sample, and is ca used by the shearing force interaction between the STM tip and the sam ple under the tip scanning. The preliminary images presented show simu ltaneously STM surface topographies and the changes of subsurface shea ring stresses in gold thin films. The sensitivity of our microscope is . 0.30 N/m for a 0.2-Hz frequency shift of the quartz crystal resonanc e frequency.