title: Study of the microstructure information of GaAs epilayers grown on silicon substrate using synchrotron radiation.
abstract: Williamson-Hall (WH) analysis is a well established method for studying the microstructural properties of epilayers grown on foreign substrates. However, the method becomes inapplicable in specific cases where the structure factor considerations and the presence of anti-phase domains forbid the data acquisition for certain reflections in conventional high-resolution X-ray diffraction (HRXRD) measurements. Here, this limitation is overcome by exploiting the large intensity (25 µW mm(-2)) and high photon energy (15.5 keV) of the X-ray beam obtained from a synchrotron radiation source. The lateral coherence length, vertical coherence length, tilt and micro-strain of GaAs epilayers grown on Si substrate have been successfully measured using the conventional WH analysis. The microstructure information obtained from the conventional WH analysis based on the data acquired at the synchrotron radiation source is in reasonable agreement with the results obtained from atomic force microscope and surface profiler measurements. Such information cannot be obtained on a laboratory-based HRXRD system where modification of the WH method by involving a set of parallel asymmetric crystallographic planes is found to be essential. However, the information obtained from the modified WH method is along a different crystallographic orientation.
authors.affiliation: Semiconductor Physics and Devices Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India.
authors.forename: Ravi
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Semiconductor Physics and Devices Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India.
authors.forename: V K
authors.initials: VK
authors.lastname: Dixit
authors.affiliation: Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Sinha
authors.affiliation: Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India.
authors.forename: Tapas
authors.initials: T
authors.lastname: Ganguli
authors.affiliation: Mechanical and Optical Support Section, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India.
authors.forename: C
authors.initials: C
authors.lastname: Mukherjee
authors.affiliation: Semiconductor Physics and Devices Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India.
authors.forename: S M
authors.initials: SM
authors.lastname: Oak
authors.affiliation: Semiconductor Physics and Devices Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India.
authors.forename: T K
authors.initials: TK
authors.lastname: Sharma
keywords: GaAs epilayers; HRXRD; Williamson–Hall analysis; coherence length; tilt; twist