MIXED GE-SI DIMER GROWTH AT THE GE SI(001)-(2X1) SURFACE/

The submonolayer growth of Ge on single domain Si(001)-(2 X 1) has bee n studied using high resolution photoemission by monitoring the Ge 3d and Si 2p core levels as functions of coverage, electron emission angl e, and annealing temperature. It is shown that Ge initially grows as a symmetric mixed Ge-Si dimers with Ge occupying the up atom and Si occu pying the down atom sites. Although this growth mode is predominant up to 0.8 monolayer coverage, pure Ge-Ge dimers do occur as well as Ge s ubstitution of second and perhaps deeper layer Si. This interdiffusion is enhanced upon annealing to 600 degrees C.