Published online by Cambridge University Press: 28 February 2011
In this brief review we consider the vacancy-related, the vacancy oxygen-related, and the vacancy-hydrogen-related defects. We note the common opportunity for chemically-driven partial dissociation of defects. With this background we briefly survey what is known of the oxygen agglomerates, noting that we favor the ylid ( the saddle-point for oxygen diffusion) as the thermal donor core, but that the (vacancy + di-oxygen) complex can also be a core, and that the latter defect can occur when the strain-energy reaches the.point that a vacancy-interstitial pair can be created, causing interstitial emission from the oxygen agglomerate. We note as well that the emission of Si≡0 is energetically favored versus emission of an unbonded interstitial.