Oxygen striation and thermally induced microdefects in Czochralski-grown silicon crystals

Abstract

Oxygen striations in Czochralski-grown silicon crystals have been directly observed by applying the scanning IR absorption technique to longitudinal sections. The oxygen striations were found to correlate clearly with thermally-induced-microdefect distributions. The results show that oxygen plays a very important role in microdefect formation. A critical oxygen concentration for microdefect introduction was estimated to be (7–8)×1017 cm−3 for 96-h, 600 °C heat treatment.

Thermally Activated Oxygen Donors In Si

“…Since the smallest wavelength attainable with the CO2 laser is 9.17 gm, whereas the peak of the oxygen absorption band is 9.04 ~m, a ratio of ao (9.04 ~m)/a (9.17 ~m) --1.95 was obtained using a Fourier transform spectrometer; this value was used for ao in the expression [O] = 4.17 X 1017 ao, generally employed for the determination of oxygen concentration (13) . 2 Both parallel faces of the Si samples were polished to a mirror finish and coated with a aingle layer quarter wavelength zinc sulfide antireflection coating to reduce the reflection coefficient and avoid interference caused by multireflections of the light beam inside the sample (14,20).…”