Scanning Tunneling Microscopy Studies of the in Desorption Process on the In/Si(111) Surface

Isothermal desorption of In atoms from the well-ordered In/Si(111) surface were studied by using ultra-high-vacuum scanning tunneling microscopy (STM). At a fixed temperature of 520℃, continuous desorption of the In adatoms from the √31×√31/√3×√3 surface induced a phase transformation into the 7×7 surface. During the desorption process, an intermediate√3×√3 surface with high concentration of substitute Si atoms was formed. The concentration of the substitutional Si adatoms in the √3×√3 regions was found to be as high as 30%. On the 7×7 surface, In atoms substituted for some Si adatoms with a preference for the edge sites compared to the corner sites. However, the population ratios between the two types of adsorption sites were not the same for the faulted and the unfaulted half unit cells. The preference for the edge site over the corner site in the unfaulted half unit cell was found to be about two times higher than that in the faulted half unit cell. KCI Citation Count: 1