DISLOCATION GOLD INTERACTION IN SILICON - THE ROLE OF DISLOCATIONS ASSINKS FOR SELF-INTERSTITIALS

The concentration of substitutional gold atoms N(Aus), transformed by the kick-out mechanism as gold diffusion proceeds in silicon, is measu red as a function of the dislocation density introduced by different d eformation procedures in FZ and Cz silicon. Two domains of dislocation density N(D) < 10(4) CM-2 and N(D) > 10(7) cm-2 in which N(Aus) was f ound to be independent of N(D) and an intermediate domain in which N(A us) varied as N(D)1/2 are observed in agreement with the theory. Howev er, a relatively wide transient zone between the N(D)1/2 law and the c onstant value above 10(7) cm-2 exists. Transmission electron microscop y observations show that, at least for low cooling rates, the dislocat ions are actually sinks for self-interstitials. In (111) FZ silicon de formed at 700-degrees-C higher values of the dislocation sink efficien cy (0.7 < gamma < 0.8) than in (100) FZ silicon deformed at 1000-degre es-C (0.3 < gamma < 0.4) are found, i.e. gamma is sensitive to the typ e of dislocation concerned. In Cz silicon very low values of gamma (0. 03) are obtained which may be enhanced up to 0.3 to 0.4 by a 1150-degr ees-C anneal.