Effect of annealing atmospheres on the void defects in large-diameter CZSi single crystals

The influence of rapid thermal annealing (RTA) atmospheres on the flow pattern defects (FPDs) was studied in this paper. Ar, N2, N2/O2(9%), N2/O2(14%) and O2 were used as the atmosphere of RTA, respectively. The experimental results showed that the FPDs density on the wafers reduced after RTA process at 1195 °C for 5 min in every atmospheres, but the decrease of FPDs depends greatly on the annealing atmosphere. In N2/O2 mixed atmosphere, the FPDs density decreased with the increase of O2 percent in the N2/O2 mixed atmosphere and is the lowest in O2 atmosphere. In addition, the densities of FPDs after RTA decreased obviously on the surface and in the region of 20 μm depth from the surface as well. The influence mechanism of annealing atmospheres on the void annihilation was also discussed according to the behavior of the vacancies and interstitial atoms affected greatly by the atmosphere of RTA.