Negative-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>U</mml:mi></mml:math>Properties for Interstitial Boron in Silicon

Abstract

Electrical detection of a single donor level of interstitial boron at ${E}_{c}\ensuremath{-}0.13$ eV using novel photo---deep-level transient spectroscopy techniques is reported. Complementary behavior between this level and the acceptor level at ${E}_{c}\ensuremath{-}0.45$ eV establishes that the defect levels have negative-$U$ ordering. The donor level exhibits a large Poole-Frenkel effect which, when properly accounted for, provides a direct and unambiguous connection to the EPR-identified interstitial boron atom. This represents the first definitive indentification of negative-$U$ properties for a defect in any solid.