Orientation-control of ge-stripes-on-insulator by narrowing in rapid-melting growth from SI(111) seed

Orientation-controlled (111)Ge-on-insulator (GOI) is essential to achieve high-carrier-mobility channel of transistors and epitaxialtemplate of functional materials. To achieve (111)-oriented GOI stripes with any stripe-directions by rapid-melting growth from (111)-oriented Si-seed, effects of stripe-width on crystal-orientations of grown layers are investigated. For ∼2-μm-stripe- width, (111)-oriented GOI stripes are achieved for growth direction along (011). However, crystal-rotation is observed for (112) direction. Such rotational-growth along (112) is suppressed by decreasing stripe-width. Consequently, (111)-oriented GOI with any stripedirections are obtained for ∼0.5-μm-stripe-width, which is attributed to strain-relaxation by narrowing. This orientation-control technique facilitates next-generation large-scale-integrated-circuits, where various functional devices are integrated on Si-platform.