DYNAMIC PROCESSES AT INP(110) SURFACES STUDIED BY UHV REFLECTION ELECTRON-MICROSCOPY

Dynamic events occurring at InP(110) surfaces as a result of thermal a nnealing have been observed in situ by reflection electron microscopy using a modified ultrahigh-vacuum transmission electron microscope equ ipped with a specimen heating holder. The motion of screw dislocations across the surface was observed at temperatures in excess of 550 degr ees C, resulting in the formation of new surface steps. Thermal dissoc iation led to desorption of P with consequent visible growth of In par ticles at 650 degrees C. Initially most In particles grew with hemisph erical shapes and linear rates of expansion. Later changes in growth r ate were associated with changes in particle shape. Three distinct par ticle shapes were observed at the end of the annealing suggesting depa rture from self-similar growth. Cooling to room temperature and overni ght ambient annealing in ultrahigh-vacuum resulted in significant chan ges in particle morphology. Genuine thermal effects were separated fro m those due to electron irradiation.