Reduction in misfit dislocation density by the selective growth of Si1−xGex/Si in small areas

Abstract

Si1−xGex and Si layers have been grown selectively in the exposed Si regions on oxide-patterned 〈100〉 oriented Si wafers using the chemical vapor deposition technique limited reaction processing. Misfit dislocation spacings at the heterointerface were measured using plan-view transmission electron microscopy in conjunction with a large-area thinning technique which allows for examination of 100–150 μm diameter areas. The dislocation density is reduced by at least a factor of 20 for small areas (lateral dimensions: tens of microns) bounded by oxide isolation when compared to adjacent large areas (millimeters) which are uninterrupted by the patterned oxide. The ability to selectively grow Si1−xGex on patterned wafers and the area-dependent reduction in dislocation density in as-grown films may be important considerations for future device applications using Si1−xGex strained layers.