Self-interstitials and related defects in irradiated silicon

Low intensity light ions (H+ or He++) irradiation of silicon introduced EPR Si-AA12 defect. Si-AA12 reveals close correlations with DLTS E1=Ec−0.39 eV minority trap. Impurity interstitials or self-interstitial associated secondary defects, such as interstitial carbon (Ci) or aluminum (Ali) or self-interstitial-oxygen complex (Sii-Oi), appear upon thermal annealing at 280-350 K and especially under injection at 77 K of Si-AA12 and E1 state. Strong 1:1 correlation between injection annealing of E1 and increasing Ci in FZ-Si and sum of (Sii-Oi)+Ci as well observed reversible transformation of Si-AA12 and E1 onto (Sii-Oi) and their re-emission after annealing (Sii-Oi) allow to attribute these states to a isolated self-interstitial. Thermally stimulated capacitance data show negative U-properties of E1 predicted by theoretical calculations and supports this identification.