Abstract

We have developed a novel technique for the measurement of stress-induced birefringence in a variety of technologically interesting thin films and bulk semiconductor materials. The approach we are utilizing could best be described as high-resolution photoelastic stress analysis.¹ The idea is very simple: a semiconductor sample under study is placed between two crossed polarizers. When there are no stresses in the sample the light is extinguished by the crossed polarizers. If stress is present in the sample this induces a small amount of birefringence which rotates the plane of polarized light. The rotation in turn allows light to pass through the second polarizer and reach a detector. The amount of light which gets through is proportional to the amount of stress in the sample. This effect has been known and used for some time; in fact it was first described theoretically by Maxwell² in 1852.

© 1988 Optical Society of America