Quenched-In Defects in CW Laser-Annealed Si

Abstract

ABSTRACTDLTS has been used to investigate the nature of CW laser-induced defects in ion-implanted Si. A dominant hole trap (∼Ev + 0.45 eV), whose concentration depends on laser power, was observed immediately after sample preparation. This defect is not stable at room temperature; instead, it decays as a function of time, transmuting to a shallow level at Ev + 0.10 eV. The recovery of the Ev + 0.45 eV level can be stimulated by low temperature thermal annealing or by minority carrier injection. By comparing these defects in laser-annealed samples with defects produced by furnace annealing followed by rapid cooling, and with other published results, the laser-induced defects have beenidentified as interstitial Fe and Fe-B pairs. Experiments suggest that elevated substrate temperature during laser annealing may inhibit the formation of these deep hole traps.