Spatially resolved residual stress assessment of GaN film on sapphire substrate by cathodoluminescence piezospectroscopy

Two cathodoluminescence piezospectroscopic (CL/PS) approaches are used for measuring the residual stress distribution in thin films and they are examined by using an intrinsic GaN film sample grown on a (0001)-oriented sapphire substrate. The CL/PS method is shown to be very effective in microscopic stress assessments and has a potential to become a routine procedure in the FE-SEM in the search for quantification/optimization of the residual stress state in thin films.