Scanning Tunneling Microscopy of HF-Controlled Si(111) Surfaces

Abstract

ABSTRACTScanning tunneling microscopy (STM) was made in order to examine the surface structure and roughness in an atomic scale. The surfaces were prepared by several ways: NH4F (pH = 8) dipping just after RCA cleaning or after keeping in dry air for a few weeks; dipping into NH4F (pH = 8) solution or dipping into solutions with pH=10 just after boiling in HNO3. The STM images clearly showed that the surface structure and roughness are dependent on the sample treatments. The smooth surfaces with less defects were obtained for surfaces prepared by removing the HNO3-oxidized layer by NH4F (pH = 8) dipping.