We present an improved photoreflectance (PR) spectroscopy technique upon the prior art in providing a rapid acquisition method of the PR spectrum in a simultaneous and multiplexed manner. Rapid PR (RPR) application is the on-line monitoring of strained silicon. Shrinkage in the silicon bandgap is measured and converted to strain, using theoretical models. Experimental RPR results are in good correlation with Raman spectroscopy.

An autofocus digital image correlation (DIC) workstation, incorporating image stacking functionality was used to perform a thermo-mechanical deformation and strain analysis of controlled collapse chip connect (C4) bumps in two FC-BGA packages. Cross-sections through the C4 bumped region were analysed through a temperature cycle from ambient temperature up to 100/spl deg/C. Strain concentrations at the C4 layer-to-die interface are revealed. Aspects of recent advances in digital image correlation technology are described in the context of this study.

This paper summarises the application of the laser-based electro-absorptive technique of photoreflectance (PR) for the study of vertical cavity surface emitting lasers (VCSELs). PR results are shown to reveal the technologically important cavity mode and ground state quantum well exciton structures. AlGaAs/GaAs based quantum well VCSELs were examined with and without top mirror layers as a function of laser pump excitation conditions, with results compared with angle-dependent PR data. Cavity mode and quantum well alignments were also studied with reference to the un-modulated reflectance signal as well as correlated with photoluminescence data. The results demonstrate the importance of PR metrology for state-of-art VCSEL characterisation.