1. a Institut fuer Werkstoffe der Elektrotechnik, University of Technology Aachen , D-52056 , Aachen , Federal Republic of Germany
2. b Dept. HL MP E TF , Siemens AG, Semiconductor Group , D-81730 , Munich , Federal Republic of Germany
3. c Symetrix Corporation , 5055 Mark Dabling Boulevard, Colorado Springs , CO