Abstract
Recently, the infrared light scattering tomography has been noticed as an observation method of defects in crystals. The tomography detects the difference of the optical properties around defects caused by crystal inperfection using the advanced technique of image processing by laser and computer. The system is easily joined with the other optical imaging systems such as EL2 distribution imaging by infrared light absorption, etc. In this paper, several interesting application of the infrared light scattering tomography on GaAs crystals have been introduced: (1) The scattering images agree well with dislocations. This result has lead us to develop new methods of stereographic observation of dislocations. (2) The images have been compared to the EL2 distribution measured by the infrared absorption on the samples before and after annealing. (3) On the In doped GaAs crystals, the disagreement between the scattering tomography and X-ray topograph has been found, which suggests the constitutional super cooling of high In content in the growth.
