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PIERS Online
Vol. 5
No. 1
2009
pp: 46-50Tunable Dynamic Capacitance Arising from Coulomb Blockade in a 2D Nanoclusters AssemblyFrédéric Peschaud, Denis Crété, Pierre Seneor, and Frédéric Nguyen Van Dau doi:10.2529/PIERS080907093628 Downloads: 360 Abstract:Radio-frequency devices such as voltage controlled oscillators (VCOs) or mixers are present in a wide variety of applications from general public electronics or telecoms to military radars. They mainly rely on variable capacitors to either tune their operating frequency or modulate their impedance. In the quest for performance and low power consumption, downscaling has been the main answer from the CMOS industry. However, this strategy will reach its limit reaching the nanometer scale. Hence, alternative ways such as the Micro ElectroMechanical Systems (MEMS) have been sought for. This paper is interested in a way Coulomb blockade of electrons in a distribution of metallic clusters embedded in the dielectric of a capacitor can be used to design a voltage controlled tunable capacitor. A layer of nanoparticles is embedded in a capacitor in tunnelling range from the first electrode in the Coulomb blockade transport regime. The first insulating layer is thin enough to make tunnel phenomenon possible on the contrary to the second one which is too thick and prevents tunnelling. The whole structure is biased via a DC source controlling the onset of Coulomb blockade according to their position in the size distribution. A small AC signal leads to a charging-discharging process of the clusters related to the total dynamic capacitance of the system. The multi-layer system is grown by sputtering. We present the model, numerical simulations and validating experiences with variable capacitors using insulating materials such as alumina or MgO.References:1. International Technology for Semiconductor, ITRS, Santa Clara, CA, 2005. [Online]. Available at http://public.itrs.net. 2. Kollberg, E. L. and A. Rydberg, "Quantum-barrier-varactor diodes for high-efciency millimeter-wave multipliers," Electronic Letters, Vol. 25, 1696-1698, 1989. 3. Ma, Q., P. Cheng, and V. Rao (Intel Corporation), "MEMS-switched stepped variable capacitor and method of making the same," US patent 653672, 2003. 4. Carrey, J., P. Seneor, N. Lidgi, H. Jaffrès, F. Nguyen Van Dau, A. Fert, A. Friederich, F. Monteigne, and A. Vaurès, "Capacitance variation of an assembly of clusters in the Coulomb blockade regime," Journal of Applied Physics, Vol. 95, 1265-1268, 2004. 5. Lambe, J. and R. C. Jacklevic, "Charge-quantization studies using a tunnel capacitor," Physical Review Letters, Vol. 22, 1371-1375, 1969. 6. Gibbons, F., A. Gongora-T, and J. V. José, "Full capacitance-matrix effects in driven Josephson-junctions arrays," Physical Review B, Vol. 58, 982-994, 1998. 7. Likharev, K. K., "Single-electron devices and their applications," Proceedings of the IEEE, Vol. 87, 606-632, 1999. 8. Nabors, K. and J. White, "Multipole-accelerated capacitance extraction algorithms for 3-D structures with multiple dielectrics," IEEE Trans. on Circuits and Systems--I: Fundamental Theory and Applications, Vol. 39, 946, 1992. 9. Hoekstra, R., H. Klunder, R. Van de Haar, E. Rouw, and P. Chand, "Circuit design with metallic single-electron tunneling junctions," ESSCIRC, 671-674, 2002. 10. [Online]. Available at www.aplac.com. 11. Peschaud, F., D. Crété, P. Seneor, and F. Nguyen Van Dau, "Concept of variable based on Coulomb blockade: A Top-down approach," ESSCIRC, 2008. 12. Lidgi, N., Transport électronique dans une assemble bidimensionnellée de nanoparticules métalliques dispersées dans une jonctions tunnel, and , Ph.D. dissertation, Paris VI Univ., 2005. |
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