The mechanism of iron gettering in boron-doped silicon

• Published in: Applied physics letters Vol. 68; no. 1; pp. 51 - 53
• Main Authors: Stolk, P. A., Benton, J. L., Eaglesham, D. J., Jacobson, D. C., Cheng, J.-Y., Poate, J. M., Myers, S. M., Haynes, T. E.
• Format: Journal Article
• Language: English
• Published: 01-01-1996
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.116754

High-energy B implantation was used to introduce gettering layers into float-zone Si wafers contaminated with 2×1014 Fe/cm3. Secondary ion mass spectrometry shows that about 5% of the Fe contamination is collected at the 4 μm deep peak of a 4×1014/cm2, 3.3 MeV B implant after annealing at 1000 °C for 1 h. Deep level transient spectroscopy demonstrates that increasing the gettering B dose from 4×1012 to 4×1014/cm2 reduces the Fe concentration from 3×1012 to below ∼1010/cm3 in the 1–3 μm deep region from the surface, indicating very efficient gettering. Measurements of the Fe depth profile imply that the depletion of Fe near the gettering layer occurs upon cooling down from 1000 °C. The gettering behavior can be qualitatively understood in terms of a Fermi-level-enhanced pairing reaction between Fe and B.