SURFACE STRUCTURES AND SURFACE CONDUCTANCE DURING METAL ADSORPTION ON SEMICONDUCTORS

Epitaxial growth modes for "two-step deposition" processes of metals on a Si(111) surface were investigated. Depth distributions of composition during the growth were analyzed by using RHEED-TRAXS (total reflection angle X-ray spectroscopy). We first made -(Ag, Au, Ga), -Sn and (4×1)-In structures, and then second metals (Ag, Au, Sn, Ga and In) were deposited on these surfaces at room temperature. Growth processes observed are classified into five growth modes: ordinary growth (O), alloying growth (A), substitution atom growth (S), particle formation growth mode (P) and floating atom growth (F). During the growth processes, we measured also surface conductivities which showed interesting behaviors. These results can be partly understood considering the growth modes, atomic arrangement, surface composition, Fermi level pinning and band bending, etc.