Micro-Raman Scattering From Hexagonal GaN, AlN, and AlxGa1-xN Grown on (111) Oriented Silicon: Stress Mapping of Cracks

摘要

We report post-growth micro-Raman stress mapping of cracks in GaN, AlN, and AlxGa1-xN grown on (111) oriented silicon. Cracks with an average spacing of approximately 100 mum are observed. These cracks are categorized into two types. The first type of crack propagates through the epilayer, and several microns deep into the substrate and is observed in all the samples investigated. The second type cracks epilayer only and is observed only in GaN. The micro-Raman stress mapping of the first type of crack shows that the epilayers are under biaxial tensile.