Spectroscopic strain measurement methodology: Degree-of-polarization photoluminescence versus photocurrent spectroscopy

A methodological approach to strain analysis in semiconductor devices is presented. Two methods, degree-of-polarization of photoluminescence and photocurrent spectroscopy, are compared by analyzing a spatially inhomogeneous strained test sample, namely, a high-power diode laser array that is affected by packaging-induced stress. Both methods concordantly reveal a −0.1% uniaxial compression in the vicinity of the midpoint of the active region of the device, demonstrating the compatibility of and justifying the assumptions involved in the two different approaches. Furthermore, we discuss some distinctive details of the processing-induced strains observed in the vicinities of metallized contacts and grooves involved in the device design.