Surface Orientation Influence on the Langmuir Evaporation Characteristics of GaAs Substrates

摘要

The dependences of congruent evaporation temperature T_c and the desorption activation energies of GaAs components on the substrate surface orientation are analyzed using Monte Carlo simulation. On the vicinal surfaces with the (111)A orientation at temperatures exceeding T_c, the metal droplets start to grow at step edges, and, with the (111)B orientation, the droplets nucleate randomly on the terraces. The droplet concentration on the (111)B surface is higher than that on the (111)A surface. The droplet-crystal interface roughness is different for (111)A and (111)B orientations. The T_c of (111)B surfaces is lower than that of (111)A surfaces. For both surface orientations, T_c decreases when the vicinal surface terrace width is shorter than the double gallium diffusion length. The gallium and arsenic desorption activation energies dependence on the vicinal surface misorientation is demonstrated. A sharp increase in the arsenic desorption rate is observed with an increase of the (111)A surface coating with liquid gallium.