Room temperature Fourier transform infrared measurements on some contaminated silicon wafers are presented. Use of subtractive techniques readily allows both carbon and oxygen concentrations of about 0.1 ppm atomic to be obtained in relatively short measurement times (about 1 min), providing an adequate "pure" wafer is used as the reference standard.
D. G. Mead and S. R. Lowry, "Evaluation of Carbon and Oxygen Content of Silicon Wafers Using Infrared Absorption," Appl. Spectrosc. 34, 167-171 (1980)