Quantitative evaluation of bulk-diffused metal contamination by lifetime techniques

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 55; no. 1; pp. 21 - 33
• Main Authors: Polignano, M.L, Bellandi, E, Lodi, D, Pipia, F, Sabbadini, A, Zanderigo, F, Queirolo, G, Priolo, F
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 14.08.1998; Elsevier
• Subjects: Bulk-diffused; Charge carriers: generation, recombination, lifetime, and trapping; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity phenomena in semiconductors and insulators; Contaminants; Defects and impurities in crystals; microstructure; Doping and impurity implantation in germanium and silicon; Electronic transport in condensed matter; Exact sciences and technology; Lifetime techniques; Physics; Structure of solids and liquids; crystallography; Contaminants; Bulk-diffused; Lifetime techniques; Photovoltaic effects; Microwave radiation; Doped materials; Measuring methods; Chromium additions; Experimental study; Impurity pair; Contamination; Impurities; Carrier lifetime; Wafers; Interstitial impurities; Surface properties; Boron additions; Impurity diffusion; SIMS; Silicon; Iron additions; Diffusion; Carrier mobility; Photoconductivity; Charge carrier injection
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/S0921-5107(98)00192-5

In this paper we present a systematic comparison among the most common methods (surface photovoltage, Elymat and microwave-detected photoconductive decay) for lifetime measurements. The possibility to identify contaminants and to quantitatively evaluate their concentration by lifetime techniques is investigated. Though these techniques are very different from each other, we show that in relation to bulk-diffused impurities, they agree very well with each other, provided that the dependence of carrier lifetime on the injection level is taken into account when comparing them. Iron and cromium implanted wafers are used in order to validate these techniques for the quantitative evaluation of bulk-diffused contaminants. Iron concentrations obtained from lifetime data are compared to measurements of chemical concentration of iron at wafer surface. A very good correlation is obtained between estimates of iron concentration from lifetime data and O 2-leak SIMS data in samples contaminated by implantation of dopant ions.