Scanning Tunneling Microscopy Barrier Height Imaging of Subsurface Dopant Atoms on Hydrogen-Terminated Si(111)

Abstract

Dopant atoms beneath a hydrogen-terminated Si(111) 1×1 surface are investigated by scanning tunneling microscopy (STM) and barrier height (BH) imaging. Because of the weak screening effect of the hydrogen-terminated Si(111) surface, subsurface donors and acceptors can be imaged by STM. From BH images, we can deduce a local change in BH at subsurface dopant sites. Both the sign and magnitude of the observed BH change are in good agreement with calculations assuming a screened Coulomb potential for a dopant potential.