Determination of Interstitial Oxygen Concentration in Low‐Resistivity n‐type Silicon Wafers by Infrared Absorption Measurements

A method is demonstrated for the measurement of interstitial oxygen with commercially available Fourier transform infrared (FTIR) equipment in device‐quality n‐type silicon wafers with resistivities as low as 0.02 Ω‐cm. The oxygen concentrations obtained using this method on a group of wafers with resistivities between 0.02 and 0.05 Ω‐cm agree with those determined by secondary ion mass spectroscopy on the same wafers with a standard deviation of 0.9 ppm. The use of FTIR standards with similar resistivities and the same surface finish on both sides as the wafers to be measured is important to the success of the determination.