1. Institut de Microtechnique, Ecole Polytechnique Fédérale de Lausanne, Optics and Photonics Technology Laboratory, Rue de la Maladière 71B, CH-2002 Neuchâtel, Switzerland
2. Swiss Federal Laboratories for Material Science and Technology, Laboratory for Electronics/Metrology/Reliability EMPA, Überlandstrasse 129, 8600 Dübendorf, Switzerland