Iron contamination in silicon technology

This article continues the review of fundamental physical properties of iro n and its complexes in silicon (Appl. Phys. A 69, 13 (1999)), and is focuse d on ongoing applied research of iron in silicon technology. The first sect ion of this article presents an analysis of the effect of iron on devices, including integrated circuits, power devices, and solar cells. Then, source s of unintentional iron contamination and reaction paths of iron during dev ice manufacturing are discussed. Experimental techniques to measure trace c ontamination levels of iron in silicon, such as minority carrier lifetime t echniques (SPV, mu-PCD. and ELYMAT), deep-level transient spectroscopy (DLT S), total X-ray fluorescence (TXRF) and vapor-phase decomposition TXRF (VPD -TXRF), atomic absorption spectroscopy (AAS), mass spectrometry and its mod ifications (SIMS, SNMS, ICP-MS), and neutron activation analysis (NAA) rue reviewed in the second section of the article. Prospective analytical tools , such as heavy-ion backscattering spectroscopy (HIBS) and synchrotron-base d X-ray microprobe techniques (XPS, XANES, XRF) are briefly discussed. The third section includes a discussion of the present achievements and challen ges of the electrochemistry and physics of cleaning of silicon wafers, with an emphasis on removal of iron contamination from the wafers. Finally, the techniques for gettering of iron are presented.