Analysis of Ni on Si-wafer surfaces using synchrotron radiation excited total reflection X-ray fluorescence analysis 1 P. Wobrauschek a , *, R. Go ¨rgl a , P. Kregsamer a , Ch. Streli a , S. Pahlke b , L. Fabry b , M. Haller c , A. Kno ¨chel c , M. Radtke c a Atominstitut der O ¨ sterreichischen Universita ¨ten, Schu ¨ttelstr. 115, A-1020 Wien, Austria b Wacker Siltronic AG, D-84479 Burghausen, Germany c Institut fu ¨r Anorganische und Angewandte Chemie, Universita ¨t Hamburg, Martin-Luther-King-Pl. 6, D-20146 Hamburg, Germany Received 26 August 1996; accepted 2 December 1996 Abstract Total Reflection X-Ray Fluorescence Analysis excited with synchrotron radiation (SR-TXRF) monochromatized by a multilayer (ML) has been used for the analysis of Ni on Si-wafer surfaces. Intentionally contaminated wafers using droplet samples have been used to determine the detection limits. Two different kinds of the geometrical arrangement of sample and detector have been compared, one of them resulting in detection limits of 13 fg for Ni. Experiments have been performed at Hasylab, Beam L using a bending magnet radiation.  1997 Elsevier Science B.V. Keywords: Total reflection; X-ray fluorescence analysis; Synchrotron radiation; Wafer analysis 1. Introduction Trace element analysis of impurities on wafer surfaces is of great importance in silicon circuit tech- nology. The demands for the next decade are ranging down to 10 7 atoms cm -2 for metal impurities on the surface. Total Reflection X-Ray Fluorescence Analysis (TXRF) is a powerful tool for the identification and quantification of chemical elements at the ultra-trace level. As TXRF is basically an energy dispersive technique, differing only in the special excitation geometry, it includes all the features of non-destruc- tiveness, simultaneous multi-element capability, high sensitivity and low background conditions which are perfectly suited for the analysis of surface contamina- tions. Also depth profiling and investigation of layered structures are typical applications. Detection limits in the range of some 100 fg (1 fg = 10 -15 g), i.e. 10 9 atoms cm -2 , have been achieved with rotating anodes and commercially available equipment [1]. Because of the high brightness of the synchrotron beam, its linear polarization in the orbital plane and its natural colli- mation, the combination of TXRF with synchrotron radiation (SR) as the excitation source (SR-TXRF) offers new possibilities to reach these challenging demands in detection limits. Using a multilayer monochromator (ML) having a wide band-pass (DE/E  0.01) transmitted from the continuum, leads Spectrochimica Acta Part B 52 (1997) 901–906 SAB 1674 0584-8547/97/$17.00  1997 Elsevier Science B.V. All rights reserved. PII S0584-8547(96)01674-6 * Corresponding author. 1 This paper was presented at the 6th Conference on ‘‘Total Reflection X-Ray Fluorescence Analysis and Related Methods’’ (TXRF ’96) held in two parts in Eindhoven (The Netherlands) and Dortmund (Germany) in June 1996, and is published in the Special Issue of Spectrochimica Acta, Part B, dedicated to that Conference.