1. Department of Electron Devices, Budapest University of Technology and Economics (formerly TUB), Budapest XI, Goldmann Gy. Te´r 3, H-1111 Hungary
2. TIMA Laboratory, 46 Avenue Fe´lix Viallet, 38031, Grenoble, Cedex France
3. MicReD Ltd., Budapest XI, Gulya´s u.27, H-1112 Hungary
4. Department of Electron Devices, Budapest University of Technology and Economics, Budapest, Hungary
5. TIMA Laboratory, 46 Avenue Fe´lix Viallet, 38031, Grenoble, Cedex, France
6. TIMA Laboratory, 46 Avenue Fe´lix Viallet, 38031 Grenoble, Cedex, France