Abstract
High quality Si/Si 1-x Ge x superlattices having layers as thin as 1.5 nm have been grown by an ultrahigh vacuum/chemical vapor deposition system. High-resolution double-crystal x-ray diffraction, and conventional and high-resolution cross-sectional transmission electron microscopy were used to evaluate the crystalline quality of these superlattices. A dynamical x-ray simulation program was employed to analyze the experimental rocking curves. Excellent matches between experimental rocking curves and simulated ones were obtained for all superlattices with various periodicity. A cross-sectional transmission electron micrograph of an 80 period Si(4.2 nm)/Si 0.878 Ge 0.122 (1.5 nm) superlattice, in which each individual layers was clearly resolved, demonstrated the capability of this growth technique for nanometer thick layer deposition.