1. Department of Electrical Engineering, KU Leuven, B-3000 Leuven, Belgium
2. IMEC, Kapeldreef 75, B-3001 Leuven, Belgium
3. Frontier Research Center, Tokyo Institute of Technology, Yokohama 226-8502, Japan
4. ASM International, B-3001 Leuven, Belgium
5. ASM International, Phoenix, Arizona 85034-7200, USA
6. Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Universiteé Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium