ISOCONCENTRATION STUDIES OF ANTIMONY DIFFUSION IN SILICON

The diffusion of Sb in Si at concentrations around its solid solubilit y has been studied by isoconcentration experiments. The samples, grown by molecular-beam epitaxy, had constant Sb-121 background dopings and a Sb-123 spike embedded in this background. The diffusion was followe d as a function of Sb background concentration at two different temper atures of 872 and 1019 degrees C by secondary ion mass spectrometry, d ifferential Hall/resistivity measurements, and transmission electron m icroscopy. At concentrations exceeding the solid solubility Sb precipi tates and interstitial-type dislocation loops were observed. At these concentrations the diffusivity decreased with increasing Sb background concentration. At concentrations below both the solid solubility and the intrinsic carrier concentration, for the highest diffusion tempera ture of 1019 degrees C, the diffusivity increases with increasing Sb b ackground doping. This behavior is discussed considering mobile Sb2V c omplexes. (C) 1997 American Institute of Physics.