Development and Application of Scanning Probe Microscopy with Externally Applied Stress and Strain
Advanced Key Technologies Division, National Institute for Materials Science
Abstract: As an active nano characterization technology, we developed an atomic resolution ultrahigh vacuum dual probe scanning probe microscope with an in-situ external stress application capability in order to determine the effects of stress and strain fields on surface atomistic structures. It is necessary to understand these effects because controlling them will be a key technology that will very likely be used in future nanometer-scale fabrication processes. We used our stress-strain filed scanning probe microscope (SF-SPM) to demonstrate atomic resolution imaging under external tensile stress and strain on the surfaces of wafers of Si(111) and Si(001). The developed SF-SPM has two operation mode, scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NCAFM) modes with atomic resolution imaging. We successfully observed domain redistribution induced by applying uniaxial stress at an elevated temperature on the surface of a wafer of vicinal Si(100). We discovered that domains for which an applied tensile stress is directed along the dimer bond become less stable and shrink. This suggests it may be feasible to fabricate single domain surfaces in a process that controls surface stress and strain.
Key words: Scanning probe microscopy, Surface stress, Surface strain, Ultrahigh vacuum, Atomic resolution