Low-temperature growth morphology of singular and vicinal Ge(001)
- Department of Materials Science and Engineering, and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)
Scanning tunneling microscopy is used to study the nonequilibrium surface morphology of singular and vicinal Ge(001) grown by molecular-beam epitaxy. Growth on substrates with {approx}0.1{degree} miscut produces patterns of nearly symmetrical growth mounds over a wide range of growth temperature, 60{lt}T{lt}230{degree}C and film thickness, 0.5{lt}h{lt}1000nm. The characteristic slope or aspect ratio of the growth mounds increases with film thickness. Analysis of the onset of mound formation gives an estimate of the Ehrlich-Schwoebel length; l{sub ES} is approximately equal to the surface lattice constant and independent of temperature. This small value for l{sub ES} implies either a weak repulsive barrier ({Delta}E{sub d}{approximately}k{sub B}T) at descending steps or a step-adatom attraction ({Delta}E{sub a}{gt}k{sub B}T) at ascending steps. Buffer layers grown at T=365{degree}C on vicinal substrates (9{degree} miscut towards [110]) show (115) facets. Low-temperature growth on vicinal surfaces (6{degree} and 9{degree} miscuts at T=155 and 230{degree}C) produces highly anisotropic growth ridges oriented along the miscut direction with larger roughness amplitude and smaller in-plane length scales than mounds produced by the same growth conditions on singular substrates. At 230{degree}C, the slopes of the growth ridges are stabilized by the (105) surface. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 614991
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 57, Issue 19; Other Information: PBD: May 1998
- Country of Publication:
- United States
- Language:
- English
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