Oxygen '96

Early Stages of Oxygen Precipitation in Silicon

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PROPERTIES OF OXYGEN AND OXYGEN-RELATED DEFECTS IN SILICON DETERMINED FROM STRESS-INDUCED ALIGNMENT STUDIES

George D. Watkins

Department of Physics, Lehigh University, Bethlehem, PA, USA

The application of uniaxial stress to a crystal can produce preferential alignment of an anisotropic defect, which, in turn, can be monitored by a variety of spectroscopic techniques. One of the earliest uses of this approach was for isolated interstitial oxygen in silicon, the sense of the alignment monitored by its IR LVM absorption confirming its squeezed position between two normally bonded silicon atoms, and the kinetics for reorientation supplying a highly accurate measure for its diffusion properties. Also very early was the study of substitutional oxygen in silicon (the A-centre), formed when interstitial oxygen traps a vacancy. In this case, simultaneous study via IR and EPR led to a remarkably detailed atomic model for the defect. Another interesting example is the carbon-oxygen pair, formed when interstitial oxygen traps a mobile interstitial carbon atom, which can be monitored by LVM, electronic excitation spectroscopy, and EPR. Direct stress alignment of the defect, plus indirect alignment achieved by first aligning the oxygen before the trapping event, has led to a detailed atomic model for the defect and its mechanism for production. Finally, we will discuss several informative clues as to the structure, identity and formation mechanism for the thermal donors that result from the application of stress during formation, plus the kinetics for recovery, as monitored by EPR and resolved electronic excitation spectra.

Last modified: Mon Feb 19 12:10:49 GMT 1996 JG