X-ray scatter based metrologies for the development of metamorphic semiconductor device structures

This work presents four key advancements to x-ray scatter based semiconductor metrology and demonstrates their application with two important new metamorphic semiconductor technologies: AlGaN/GaN and AlSb/InAs based mHEMTs. First a new method for directing x-ray diffractometer movement through reciprocal space is presented. Next, a new approach to simulating measurements of defective mosaic crystals using kinematical theory is described. This is followed by derivation of a new analytical alloy composition calculation and elucidation of a numerical methodology accounting for composition dependent crystal elasticity and thermal deformation. Finally, a new method for enhancing Fourier transforms of x-ray scatter data is presented.; Kinematical mosaic simulations of GaN reciprocal space maps yield excellent agreement with XTEM dislocation analysis. Composition and relaxation measurements of AlGaN buffer layers are demonstrated to be accurate and represent a nearly tenfold throughput improvement over traditional approaches. Enhanced Fourier analysis is shown to be extremely effective in extracting AlGaN barrier layer thicknesses from reflectivity scans with excellent correlation to traditional analysis and STEM measurements. Directed reciprocal space scans combined with traditional dynamical simulations are shown to be effective at characterizing misfit strain relaxation, composition, and thickness of several layers in the complicated AlSb/InAs mHEMT structure. Similarly, enhanced discrete Fourier transforms of reflectivity scans are shown to be useful in efficiently determining several AlSb/InAs mHEMT layer thicknesses.