1. a Department of Metallurgy and Science of Materials, Parks Road , University of Oxford , Oxford , OX1 3PH , England
2. d Universität Göttingen , Göttingen , F.R. Germany
3. e Siemens AG , Otto-Hahn-Ring 6, 8000 , München , 83 , F.R. Germany
4. b Philips Components , Millbrook Industrial Estate Southampton SO9 7BH, England
5. f Monsanto Electronic Materials Co. , Featherstone Road, Wolverton Mill South, Milton Keynes, Buckinghamshire MK12 5TB, England
6. c J. J. Thomson Physical Laboratory , University of Reading , Whiteknights, Reading , RG6 2AF , England
7. g SERC, Daresbury Laboratory , Warrington , WA4 4AD , England