Mechanism of iron gettering in MeV Si ion implanted epitaxial silicon

The gettering properties of the two damage regions, namely, a near-surface vacancy-rich region, R_p/2 and a buried layer of extended defects near the MeV Si ion projected range, R_p, have been quantitatively determined by means of secondary ion mass spectrometry and deep level transient spectroscopy techniques. To isolate the simultaneous and competitive gettering between iron and oxygen, the MeV defects were introduced into epitaxial silicon doped with boron. Czochralski Si samples were also used for comparison. Experiments on isochronal and isothermal annealing of Fe contaminated samples in conjunction with the rapid quenching procedure allowed us to establish the dominating gettering mechanisms in the two damage regions. Thus, gettering in the R_p region was driven by relaxation of supersaturated Fe, while the segregation-induced gettering mechanism was operative in the R_p/2 zone. As a result, the concentration of Fe, which was remained ungettered at elevated temperature, was well below the solid solubility limit. The major gettering parameters of MeV defects, such as gettering capacity, efficiency, and thermal stability have been determined. © 1998 American Institute of Physics.