Atomic force microscopy studies of self-assembled Si1-xGex islands produced by controlled relaxation of strained films

Self-assembled Si1-xGex islands were studied in detail using atomic force microscopy. The self-assembled Si1-xGex islands were formed by a novel two-step process. First, highly strained Si1-xGex thin films (with x similar to0.4) were selectively grown on a silicon wafer by chemical vapor deposition at 650 degreesC. The growth was followed by an annealing step performed in hydrogen at 750 degreesC at reduced pressure conditions for specific times. The size and distribution of the islands was found to be a function of the annealing conditions and an ordered pattern could be achieved with specific annealing conditions. This growth process shows a new way of creating device islands, which are confined within oxide regions and could be ordered, for applications in optical and electronic devices on silicon. (C) 2001 American Vacuum Society.