In Situ Observation of Oxygen Precipitation in Silicon with High Energy X-Rays
Oxygen precipitation in silicon has been studied in-situ by high energy X-ray diffraction. A gain of diffracted intensity is expected if an ideal crystal is distorted by growing precipitates as the diffraction mode changes from a dynamical to a more kinematical one. Irreversible changes in the intensity of a 220 and a 400 Bragg peak are detected for Czochralski grown samples only, but not in a float zone grown reference crystal. Thus, these changes are attributed to oxygen precipitation, which is confirmed by a subsequent classical ex-situ characterization. Further, the changes of the intensities of the two measured Bragg peaks are compared to each other to get the level of change in the diffraction mode from a dynamical to a kinematical one. The detection limit of the specific setup is estimated via a simulation of the defect inventory to correspond to a precipitate diameter of 50nm with the density of 6.9•109 1/cm3. The diffraction experiments are done with polychromatic and divergent X-rays generated by a laboratory source, albeit with high energy. This results in a simple and accessible setup for the characterization of oxygen precipitates.
M. Kittler and H. Richter
H. Grillenberger and A. Magerl, "In Situ Observation of Oxygen Precipitation in Silicon with High Energy X-Rays", Solid State Phenomena, Vols. 156-158, pp. 437-441, 2010