LOW-ENERGY-ELECTRON DIFFRACTION ANALYSIS ON INITIAL-STAGES OF GE GROWTH ON SI(111)(1X1)-AS AND AS-DESORBED SI(111)(1X1) SURFACES

We have investigated initial stages of Ge growth on Si(1 x 1)-As and A s-desorbed (1 x 1) surfaces using spot profile analysis of low-energy electron diffraction and Auger electron spectroscopy. It is found that at 500 degrees C, 2-dimensional (2D) islands are formed on both the S i(1 x 1)-As and the As-desorbed (1 x 1) surface. In contrast, Ge growt h on the Si(1 x 1)-As surfaces at 300 degrees C initially proceeds in the step Bow mode, while for growth on the As-desorbed (1 x 1) surface s at 300 degrees C, much smaller 2D islands are formed. We demonstrate d that the effect of As surfactant on surface diffusion is deeply rela ted to the growth temperatures, and that As atoms enhance migration of Ge atoms at lower growth temperatures.