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Vol: 57(71) No: 4 / December 2012 Effect of Layer Thicknesses on the Memory Hysteresis of MNOS Structures – Results of Computer Simulations K. Z. Molnár Institute of Microelectronics and Technology, Óbuda University, Kandó Kálmán Faculty of Electrical Engineering, Tavaszmező u. 15-17, H-1084 Budapest, Hungary, phone: (361) 6665054, e-mail: Molnar.Karoly@kvk.uni-obuda.hu Zs. J. Horváth Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute for Technical Physics and Materials Science, Konkoly Thege Miklós u. 29-33, H-1121 Budapest, Hungary, phone: (361) 6665145, e-mail: horvzsj@mfa.kfki.hu Keywords: computer simulation, silicon nitride, MNOS, non-volatile memory, tunneling current, memory hsyteresis Abstract Electron and hole tunneling probability is calculated and memory hysteresis behaviour of MNOS structures are simulated by integrating the difference of the current via the oxide and nitride layer. The effect of the oxide and nitride thickness as well as the depth of charge centroid is studied. The results indicate that the optimal oxide thickness is about 2 nm. A thin nitride layer decreases the efficiency of the injected charge. It has been obtained that the possible highest memory window width decreases monotonically with increasing depth of charge centroid. References [1] P. Normand, E. Kapetanakis, P. Dimitrakis, D. Skarlatos, K. Beltsios, D. Tsoukalas, C. Bonafos, G. Ben Assayag, N. Cherkashin, A. Claverie, J.A. Van Den Berg, V. Soncini, A. Agarwal, M. Ameen, M. Perego, M. Fanciulli, \"Nanocrystals manufacturing by ultra-low-energy ion-beam synthesis for non-volatile memory applications\", Nucl. Instr. and Meth. B, 216, 228-238, 2004, and references therein. [2] P. Dimitrakis, E. Kapetanakis, D. Tsoukalas, D. Skarlatos, C. Bonafos, G. Ben Assayag, A. Claverie, M. Perego, M. Fanciulli, V. Soncini, R. Sotgiu, A. Agarwal, M. Ameen, Ch. Sohl, P. Normand, \"Silicon nanocrystal memory devices obtained by ultra-low-energy ion-beam synthesis\", Solid-State Electron., 48, (9), 1511-1517, 2004. [3] B. De Salvo, C. Gerardi, R. van Schaijk, S. A. Lombardo, D. Corso, C. Plantamura, S. Serafino, G. Ammendola, M. van Duuren, P. Goarin, W. Y. Mei, K. van der Jeugd, T. Baron, M. Gély, P. Mur, .S. Deleonibus, \"Performance and Reliability Features of Advanced Nonvolatile Memories Based on Discrete Traps (Silicon Nanocrystals, SONOS)\", IEEE Trans. Dev. Mater. Reliability, 4, (3), 377-389, 2004, and references therein. [4] B. Pődör, Zs. J. Horváth, P. Basa (Eds.), \"Semiconductor Nanocrystals; Proc. First Int. Workshop on Semiconductor Nanocrystals SEMINANO2005, Sept. 10-12, 2005, Budapest, Hungary\" Vols. 1 and 2. [5] Zs. J. Horváth, \"Semiconductor nanocrystals in dielectrics: Optoelectronic and memory applications of related silicon based MIS devices\", Current Appl. Phys., 6, (2), 145-148, 2006, and references therein. [6] C.L. Heng, N.W. Teo, Vincent Ho, M.S. Tay, Y. Lei, W.K. Choi, W.K. Chim, \"Effects of rapid thermal annealing time and ambient temperature on the charge storage capability of SiO/pure Ge/rapid thermal oxide memory structure\", Microel. Eng., 66, 218-223, 2003. [7] A. Dana, I. Akca, O. Ergun, A. Aydinli, R. Turan, T.G. Finstad, \"Charge retention in quantized energy levels of nanocrystals\", Physica E, 38, (1-2), 94-98, 2007. [8] Zs. J. Horváth, P. Basa, T. Jászi, A. E. Pap, L. Dobos, B. Pécz, L. Tóth, P. Szöllősi, K. Nagy, \"Electrical and memory properties of Si3N4 MIS structures with embedded Si nanocrystals\", J. Nanosci. Nanotechnol., 8, 812, 2008. [9] Zs. J. Horváth, P. Basa, \"Chapter 5: Nanocrystal memory structures\" in: Nanocrystals and Quantum Dots of Group IV Semiconductors, (Eds. T. V. Torchynska, Yu. V. Vorobiev), American Scientific Publishers, 2010, 225. [10] Zs. J. Horváth, P. Basa, \"Nanocrystal non-volatile memory devices\", Mater. Sci. Forum, 609, 1, 2009. [11] D. Frohman-Bentchkowsky, M. Lenzlinger, “Charge Transport and Storage in Metal-Nitride-Oxide-Silicon (MNOS) Structures,” J. Appl. Phys. 40, (1969) 3307. [12] K. I. Lundström, C. M. Svensson, “Properties of MNOS Structures,” IEEE Trans. El. Dev., ED-19 (1972) 826. [13] Zs.J.Horváth, \"Ocenka gisterezisa MNOP elementov pam\'ati\", Proc. 3rd Int. Sci. Coll. T.U. Ilmenau, Oct. 30 - Nov. 3, 1978, Ilmenau, GDR, Heft 7, 81. [14] Zs.J.Horváth, \"Memory hysteresis measurements on silicon oxynitride films\", Solid-State Electron. 23, 1053-1054, 1980 [15] Zs. J. Horváth, V. Hardy, \"Simulation of memory behaviour of non-volatile structures\", J. Nanosci. Nanotechnol., 8, 834–840, 2008. [16] P. Basa, Zs. J. Horváth, T. Jászi, A. E. Pap, L. Dobos, B. Pécz, L. Tóth, P. Szöllősi, “Electrical and memory properties of silicon nitride structures with embedded Si nanocrystals,” Physica E, 38 (2007) 71. [17] Zs. J. Horváth, K. Z. Molnár, Gy. Molnár, P. Basa, T. Jászi, A. E. Pap, R. Lovassy, P. Turmezei, “Charging behaviour of MNOS structures with embedded Ge nanocrystals,” Phys. Stat. Sol. (C), 9, 1370, 2012. [18] K. Z. Molnár, P. Turmezei, Zs. J. Horváth, \"Charging behaviour of MNOS and SONOS memory structures with embedded semiconductor nanocrystals - Computer simulation\", MRS Online Proc. Library, to be published. [19] Zs. J. Horváth, P. Basa, T. Jászi, K. Z. Molnár, A. E. Pap, Gy. Molnár, \"Charging behaviour of silicon nitride based non-volatile memory structures with embedded semiconductor nanocrystals\", Appl. Surf. Sci., in press. |