Selective growth of GaAs and associated faceting and lateral overgrowth on nanoscale SiO/sub 2/-patterned GaAs[100] by molecular beam epitaxy

We report selective growth of GaAs on a 350-nm period 2-dimensional (2D) SiO/sub 2/-patterned GaAs[100] substrate by molecular beam epitaxy. Gallium atoms incident on SiO/sub 2/ surface undergo adsorption and evaporation different from those on GaAs surface. At high growth temperature (/spl sim/ 615/spl deg/C - 630/spl deg/C) when Ga growth rate is about 0.1 monolayer/s, Ga atoms are largely desorbed from a SiO/sub 2/ surface while they are deposited on GaAs surface with sticking coefficient close to unity. To examine selective growth, 350-nm period 2D arrays of circular openings on GaAs [100] of the diameter less than 200 nm were prepared on a SiO/sub 2/-covered GaAs substrate by large-area interferometric lithography and dry etching, and about 100-nm thick GaAs was deposited on this substrate. Under the growth conditions mentioned above, homoepitaxial selective growth of GaAs on a SiO/sub 2/-patterned substrate relying on the negligible sticking coefficient of Ga atoms on SiO/sub 2/ surface is realized. Because of lateral growth, a circular opening on GaAs[100] is filled by a square-shape GaAs epi-island in the top view SEM image. Additional experimental results of faceting and lateral growth on a nanoscale SiO/sub 2/-patterned substrate will be presented.