The use of two-sided surface photovoltage methods, involving the measurement of SPV from both wafer-sides was proposed as an approach to monitoring iron contamination of silicon. The method was applied to the diffusion of implanted iron in lightly-doped p-type silicon during rapid thermal annealing. A good correlation was found between the iron distribution and rapid thermal annealing at 375 to 1100C. The effect of thermal donors in silicon after rapid thermal annealing at below 700C was illustrated. The proportion of iron detectable by SPV (FeB pairs) was found as a function of rapid thermal annealing time and temperature. The diffusion activation energy was deduced for interstitial ionized iron, Fei+, and for interstitial neutral iron, Fei0. Low thermal-budget rapid thermal annealing, combined with TS-SPV, proved to be an effective iron-contamination monitoring means; identifying sources, character and location.

Two-Side Surface Photovoltage Studies for Implanted Iron Diffusion in Silicon during Rapid Thermal Anneal. I.Rapoport, P.Taylor, J.Kearns, D.K.Schroder: Journal of Applied Physics, 2010, 107[1], 013518