A new optical technique for characterization of technological semiconductor wafers

A new non-destructive method for visualization of free carrier accumulations in standard semiconductor wafers is being proposed. This method has been developed on the basis of the conventional low-angle mid-IR-light-scattering technique and dark field microscopy. Being sensitive to low concentrations of free carriers in the accumulations, the method allows mapping and investigation of technological semiconductor wafers for determination of the distribution of free carrier accumulations. The method has been applied to visualization of large-scale electrically active defect accumulations in a number of semiconductor crystals. thod may be applied for both scientific research and wafer incoming and step inspection directly in a technological cycle. rspectives for further development of the technique proposed are also discussed in the paper.