Infrared characterization of oxygen precipitates in silicon wafers with different concentrations of interstitial oxygen

The study of the optical behavior of oxygen in silicon is presented, based on infrared absorption measurements performed at liquid helium temperature. A total of six groups of silicon wafers characterized by different initial concentrations of interstitial oxygen from ∼2×1017 to ∼1018 atoms cm−3 were analysed. The experimental conditions were chosen so as to distinguish the contributions from interstitial and precipitated oxygen, while the thermal treatment of the samples was studied in order to cause the growth of the grown-in precipitates. The relative concentrations of platelet and spheroid precipitates grown after the thermal treatment of the wafers are discussed.