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We report the analysis of lateral composition modulation in (InAs)[sub m]/(GaSb)[sub m] superlattices by x-ray diffraction. Vertical and lateral satellite peaks for a 140 period structure were observed. The lateral modulation wavelength, average superlattice composition, and vertical superlattice wavelength were determined. The lateral modulation was observed only along one in-plane direction resulting in quantum wire-like structures along the [1&1macr;0] direction. The unconventional structure of the lateral composition modulation, in which the stacking of the layers leads to a doubling of the vertical superlattice period, is discussed. [ABSTRACT FROM AUTHOR]

We present quantitative characterization of atomic ordering in semiconductor alloy films by x-ray diffractometry. In particular, we show that the order parameter of CuPt-B ordered GaInP[sub 2] films can be determined without measuring the fundamental reflections or examining structural details of the ordered domains. Our method is based on the fact that the ordering peak is modulated by statistical displacements of atom planes, which is a function of the degree of ordering. Therefore, by comparing two or more ordering peaks in an x-ray spectrum, the order parameter of an ordered film can be extracted solely for those regions that are, in fact, ordered. The method can straightforwardly be extended to other ordered alloys. [ABSTRACT FROM AUTHOR]

High-quality strain-relaxed SiGe templates with a low threading dislocation density and smooth surface are critical for device performance. In this work, SiGe films on low temperature Si buffer layers were grown by solid-source molecular beam epitaxy and characterized by atomic force microscope, double-axis x-ray diffraction, photoluminescence spectroscopy, and Raman spectroscopy. Effects of the growth temperature and the th density as well as smooth surface was obtained by this method. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report the results of a detailed x-ray diffraction analysis of two AlxIn1-xAsySb1-y/GaSb multilayer samples grown by molecular beam epitaxy on GaSb (100). The kinematical scattering theory was used to fit the x-ray diffraction intensity profiles to determine the lattice spacing, composition, and strain of the multilayers, allowing for interdiffusion between the layers and variation in the multilayer wavelength. It has been determined that the quaternary alloy composition varies throughout the layer and that there is an interfacial quaternary layer that differs in composition from that of the bulk AlxIn1-xAsySb1-y layer. A rationale for this graded composition and interfacial layer will be discussed based on the growth dynamics for this system. [ABSTRACT FROM AUTHOR]

Relaxed SiGe attracted much interest due to the applications for strained Si/SiGe high electron mobility transistor, metal-oxide-semiconductor field-effect transistor, heterojunction bipolar transistor, and other devices. High-quality relaxed SiGe templates, especially those with a low threading dislocation density and smooth surface, are critical for device performance. In this work, SiGe films on low-temperature Si buffer layers were grown by solid-source molecular-beam epitaxy and characterized by atomic force microscope, double-axis x-ray diffraction, and photoluminescence spectroscopy. It was demonstrated that, with the proper growth temperature and Si buffer thickness, the low-temperature Si buffer became tensily strained and reduced the lattice mismatch between the SiGe and the Si buffer layer. This performance is similar to that of the compliant substrate: a thin substrate that shares the mismatch strain in heteroepitaxy. Due to the smaller mismatch, misfit dislocation and threading dislocation densities were lower. [ABSTRACT FROM AUTHOR]