INFRARED SPECTROPHOTOMETER

摘要

PURPOSE:To accurately measure the infrared-ray absorption coefficient of a semiconductor wafer so that the absorpfion coefficient can be measured even from wafers having a mirror surface on one side. CONSTITUTION:A transmission type sample holder 7 is provided between a light source 1 and infrared detector 8 and, at the same time, a polarization beam splitter 5 is provided between the holder 7 and a spectroscope 4. The holder 7 is provided so that the holder 7 can be freely rotated around an axis perpendicular to the optical axis by means of an automatic rotary stage 9. The holder 7 is set so that the p-polarized component of infrared rays separated by means of the splitter 5 can be made incident to a sample wafer at the Brewster angle and the sample wafer is irradiated with the p-polarized component of the infrared rays. Since the p-polarized component is completely made incident to the sample wafer without being reflected by the surface of the wafer, the transmissivity and absorption coefficient of the wafer can be accurately measured. While the optical axis is deviated by refraction when the infrared rays are transmitted through the sample wafer, the deviation is corrected by using an integrating sphere 11.