Wet Preparation of Defect-Free Hydrogen-Terminated Silicon Wafer Surface and Its Characterization in Atomic-Scale

摘要

We tried to develop a new wet preparation method for an atomically defect-free Si wafer surface. In conventional atomically smooth treatment using NH_4F aqueous solution, dissolved oxygen was revealed to form defects on the Si (111) surface. We achieved the formation of an extremely atomically smooth hydrogen-terminated surface with good periodic step/terrace structure using low disolved oxygen NH_4F etchant. Moreover, the ordered surface structure was confirmed to be fabricated all over the wafer surface montering organic contanination using UHV-STM. It was found that the terrace width could be controlled by setting a suitable off-angle in the wafer-polishing process, and the phenomenon was succcesufly explained using Monte-Cairo sumilation of etching process. The atomic-scale defect-free hydrogen-terminated wafer surface with periodic step/terrace structure is greatly expected to be useful as a well-defined substrate for nanostructure fabrication.