Characterization of defects in semiconductor materials by infrared piezobirefringence

A simulation procedure for observation of dislocation images in single-crystal silicon samples of {100} orientation using infrared piezobirefringence is presented. The simulated and the experimentally observed images of dislocations are given, and the variation of the images with respect to the angle of polarization of the incident light is shown. Simulation shows that for dislocations oriented along the images of pure edge dislocations and pure screw dislocations are different in nature when viewed along the principal crystal direction [100]. Also, for the same case, the image of a pure edge dislocation is found to be the brightest with a four-petal rosette pattern with equal lobes when the polarizer makes an angle of 45° with respect to the dislocation slip plane, whereas under the same conditions, the image of a pure screw dislocation is found to be totally extinct