Resistive random access memory (RRAM) has recently attracted great attention due to its potential for replacement of flash memory in next-generation nonvolatile memory applications. In this thesis, we have investigated the resistive switching property of doping Al in HfO2-based RRAM. The Al-doped HfO2 films were prepared as multistack-like structure on TiN/Ti/SiO2/Si substrate by atomic layer deposition (ALD), which can control the film thickness precisely with high coverage ability. Moreover, in order to make Al diffuse more evenly through whole HfO2 film, post-deposition annealing had been done before depositing Pt top electrode by DC sputtering. The effect of Hf/Al ratio would also be discussed, and the proportion of doped-Al was controlled by ALD cycle repeat. The HfO2-based RRAM shows a bipolar resistive switching behavior that the positive bias induces a low resistance state and the negative bias resets to the relative high resistance state. The improved uniformity of resistive switching characteristics in the Al-doped HfO2 thin film RRAM is demonstrated. More physical details is also obtained from thermal I-V curve analysis.

[1] Evalueserve, “Non-volatile Memory Market,” BCC Research, SMC060A, July 2005.
[2] H. Y. Lee, P. S. Chen, T. Y. Wu, Y. S. Chen, C. C. Wang, P. J. Tzeng, C. H. Lin, F. Chen, C. H. Lien, and M. J. Tsai, “Low power and high speed bipolar switching with a thin reactive Ti buffer layer in robust HfO2 based RRAM,” 2008 IEEE International Electron Devices Meeting, 2008, p. 297-300.
[3] Z. Fang, H. Y. Yu, W. J. Liu, Z. R. Wang, X. A. Tran, B. Gao, and J. F. Kang, “Temperature Instability of Resistive Switching on HfOx-Based RRAM Devices,” vol. 31, 2010, p. 476-478.
[4] H. Y. Lee, P. S. Chen, C. C. Wang, S. Maikap, P. J. Tzeng, C. H. Lin, L. S. Lee, and M. J. Tsai, “Low-Power Switching of Nonvolatile Resistive Memory Using Hafnium Oxide,” Japanese Journal of Applied Physics, vol. 46, Apr. 2007, pp. 2175-2179.
[5] C. Walczyk, C. Wenger, R. Sohal, M. Lukosius, A. Fox, J. Dąbrowski, D. Wolansky, B. Tillack, H. J. Mussig, and T. Schroeder, “Pulse-induced low-power resistive switching in HfO2 metal-insulator-metal diodes for nonvolatile memory applications,” Journal of Applied Physics, vol. 105, 2009, p. 114103.
[6] H. Zhang, B. Gao, B. Sun, G. Chen, L. Zeng, L. Liu, X. Liu, J. Lu, R. Han, J. Kang, and B. Yu, “Ionic doping effect in ZrO2 resistive switching memory,” Applied Physics Letters, vol. 96, 2010, p. 123502.
[7] C. Muller, “Emerging Concepts in Non-volatile Memory Technologies - Era of Resistance Switching Memories,” 2008 IEEE Computer Society Annual Symposium on VLSI, 2008, p. 3.
[8] G. Muller, T. Happ, M. Kund, G. Y. Lee, N. Nagel, and R. Sezi, “Status and outlook of emerging nonvolatile memory technologies,” IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004, p. 567-570.
[9] 簡昭欣、呂正傑、陳志遠、張茂男、許世祿、趙天生, “先進記憶體簡介,” 國研科技創刊號
[10] 劉志益、曾俊元, “電阻式非揮發記憶體之近期發展”
[11] G. Muller, N. Nagel, C. U. Pinnow, and T. Rohr, “Emerging non-volatile memory technologies,” ESSCIRC 2004, p. 37-44.
[12] 葉林秀、李佳謀、徐明豐、吳德和, “磁阻式隨機存取記憶體技術的發展 — 現在與未來,” 2004, p. 607-619.
[13] W. Y. Chang, “Characteristics of (Pr,Ca)MnO3 thin films on LaNiO3-electrodized Si substrate for nonvolatile resistance random access memory application,” Master thesis, National Tsing Hua University, July 2006.
[14] I. G. Baek, M. S. Lee, S. Sco, M. J. Lee, D. H. Seo, D. S. Suh, J. C. Park, S. O. Park, H. S. Kim, I. K. Yoo, U. I. Chung, and J. T. Moon, “Highly scalable non-volatile resistive memory using simple binary oxide driven by asymmetric unipolar voltage pulses,” IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004., p. 587-590.
[15] S. Q. Liu, N. J. Wu, and A. Ignatiev, “Electric-pulse-induced reversible resistance change effect in magnetoresistive films,” Applied Physics Letters, vol. 76, 2000, p. 2749.
[16] A. Sawa, T. Fujii, M. Kawasaki, and Y. Tokura, “Hysteretic current–voltage characteristics and resistance switching at a rectifying Ti／Pr0.7Ca0.3MnO3 interface,” Applied Physics Letters, vol. 85, 2004, p. 4073.
[17] A. Beck, J. G. Bednorz, C. Gerber, C. Rossel, and D. Widmer, “Reproducible switching effect in thin oxide films for memory applications,” Applied Physics Letters, vol. 77, 2000, p. 139.
[18] C. Rossel, G. I. Meijer, D. Bre’maud, and D. Widmer, “Electrical current distribution across a metal-insulator-metal structure during bistable switching,” Japanese Journal of Applied Physics, vol. 90, 2001, p. 2892.
[19] L. P. Ma, J. Liu, S. Pyo, and Y. Yang, “Organic bistable light-emitting devices,” Applied Physics Letters, vol. 80, 2002, p. 362.
[20] L. P. Ma, J. Liu, and Y. Yang, “Organic electrical bistable devices and rewritable memory cells,” Applied Physics Letters, vol. 80, 2002, p. 2997.
[21] S. Seo, M. J. Lee, D. H. Seo, E. J. Jeoung, D. S. Suh, Y. S. Joung, I. K. Yoo, I. R. Hwang, S. H. Kim, I. S. Byun, J. S. Kim, J. S. Choi, and B. H. Park, “Reproducible resistance switching in polycrystalline NiO films,” Applied Physics Letters, vol. 85, 2004, p. 5655.
[22] A. Asamitsu, Y. Tomioka, H. Kuwahara, and Y. Tokura, “Current switching of resistive states in magnetoresistive manganites,” Nature, vol. 388, 1997, p. 1995-1997.
[23] Y. Tokura, “Colossal magnetoresistive manganites,” Journal of Magnetism and Magnetic Materials, vol. 200, 1999, p. 1-23.
[24] R. Yang, X. M. Li, W. D. Yu, X. D. Gao, D. S. Shang, X. J. Liu, X. Cao, Q. Wang, and L. D. Chen, “The polarity origin of the bipolar resistance switching behaviors in metal/La0.7Ca0.3MnO3/Pt junctions,” Applied Physics Letters, vol. 95, 2009, p. 072105.
[25] W. Y. Chang, Y. C. Lai, T. B. Wu, S. F. Wang, F. Chen, and M. J. Tsai, “Unipolar resistive switching characteristics of ZnO thin films for nonvolatile memory applications,” Applied Physics Letters, vol. 92, 2008, p. 022110.
[26] K. M. Kim, B. J. Choi, Y. C. Shin, S. Choi, and C. S. Hwang, ”Anode-interface localized filamentary mechanism in resistive switching of TiO2 thin films,” Applied Physics Letters, vol. 91, 2007, p. 012907.
[27] R. Waser and M. Aono, “Nanoionics-based resistive switching memories.,” Nature materials, vol. 6, 2007, p. 833-840.
[28] A. Sawa, “Resistive switching in transition metal oxides,” Materials Today, vol. 11, 2008, p. 28-36.
[29] K. Kinoshita, T. Tamura, M. Aoki, Y. Sugiyama and H. Tanaka, “Bias polarity dependent data retention of resistive random access memory consisting of binary transition metal oxide,” Applied Physics Letters, vol. 89, 2006, p. 103509.
[30] K. M. Kim, B. J. Choi, and C. S. Hwang, “Localized switching mechanism in resistive switching of atomic-layer-deposited TiO2 thin films,” Applied Physics Letters, vol. 90, 2007, p. 242906.
[31] U. Russo, D. Ielmini, C. Cagli, and A. L. Lacaita, “Self-Accelerated Thermal Dissolution Model for Reset Programming in Unipolar Resistive-Switching Memory (RRAM) Devices,” IEEE Transactions on Electron Devices, vol. 56, 2009, p. 193-200.
[32] U. Russo, S. Member, D. Ielmini, C. Cagli, A. L. Lacaita, and S. Member, “Filament Conduction and Reset Mechanism Memory ( RRAM ) Devices,” vol. 56, 2009, p. 186-192.
[33] K. Szot, W. Speier, G. Bihlmayer, and R. Waser, “Switching the electrical resistance of individual dislocations in single-crystalline SrTiO3,” Nature materials, vol. 5, 2006, p. 312-320.
[34] D. H. Kwon, K. M. Kim, J. H. Jang, J. M. Jeon, M. H. Lee, G. H. Kim, X. S. Li, G. S. Park, B. Lee, S. Han, M. Kim, and C. S. Hwang, “Atomic structure of conducting nanofilaments in TiO2 resistive switching memory.,” Nature nanotechnology, vol. 5, 2010, p. 148-153.
[35] K. Tsubouchi, I. Ohkubo, H. Kumigashira, M. Oshima, Y. Matsumoto, K. Itaka, T. Ohnishi, M. Lippmaa, and H. Koinuma, “High-Throughput Characterization of Metal Electrode Performance for Electric-Field-Induced Resistance Switching in Metal/Pr0.7Ca0.3MnO3/Metal Structures,” Advanced Materials, vol. 19, 2007, p. 1711-1713.
[36] A. Baikalov, Y. Q. Wang, B. Shen, B. Lorenz, S. Tsui, Y. Y. Sun, Y. Y. Xue, and C. W. Chu, ” Field-driven hysteretic and reversible resistive switch at the Ag–Pr0.7Ca0.3MnO3 interface” Applied Physics Letters, vol. 83, 2003, p. 957.
[37] S. Tsui, A. Baikalov, J. Cmaidalka, Y. Y. Sun, Y. Q. Wang, Y. Y. Xue, C. W. Chu, L. Chen, and a J. Jacobson, “Field-induced resistive switching in metal-oxide interfaces,” Applied Physics Letters, vol. 85, 2004, p. 317.
[38] X. Chen, N. J. Wu, J. Strozier, and A. Ignatiev, “Direct resistance profile for an electrical pulse induced resistance change device,” Applied Physics Letters, vol. 87, 2005, p. 233506.
[39] T. Fujii, M. Kawasaki, a Sawa, H. Akoh, Y. Kawazoe, and Y. Tokura, “Hysteretic current–voltage characteristics and resistance switching at an epitaxial oxide Schottky junction SrRuO3／SrTi0.99Nb0.01O3,” Applied Physics Letters, vol. 86, 2005, p. 012107.
[40] R. Fors, S. Khartsev, and A. Grishin, “Giant resistance switching in metal-insulator-manganite junctions: Evidence for Mott transition,” Physical Review B, vol. 71, 2005, p. 1-10.
[41] M. J. Rozenberg, I. H. Inoue, and M. J. Sanchez, “Strong electron correlation effects in nonvolatile electronic memory devices,” Applied Physics Letters, vol. 88, 2006, p. 033510.
[42] C. H. Chen, “Study on the HfO2-TiO2 thin films for Resistance Random Access Memory,” Master thesis, National Tsing Hua University, July 2009.
[43] S. M. Sze, Kwok K. Ng, “Physics of Semiconductor Devices,” 3rd edition, Wiley-interscience, 2007, p.227-228.
[44] T. Hori, “Gate dielectrics and MOS ULSIs：principle, technologies, and applications,” Springer, Berlin, 1997, p.8-45.
[45] S. C. Hung, “Characteristics of nickel oxide thin films for resistance random access memory application,” Master thesis, National Cheng Kung University, June 2008.
[46] J. Lee, J. Shin, D. Lee, W. Lee, S. Jung, M. Jo, J. Park, K. P. Biju, S. Kim, S. Park, and H. Hwang, “Diode-less Nano-scale ZrOx/HfOx RRAM Device with Excellent Switching Uniformity and Reliability for High-density Cross-point Memory Applications,” IEDM, 2010, p. 452-455.
[47] S. Yu, B. Gao, H. Dai, B. Sun, L. Liu, X. Liu, R. Han, J. Kang, and B. Yu, “Improved Uniformity of Resistive Switching Behaviors in HfO2 Thin Films with Embedded Al Layers,” Electrochemical and Solid-State Letters, vol. 13, 2010, p. H36.
[48] H. Zhang, L. Liu, B. Gao, Y. Qiu, X. Liu, J. Lu, R. Han, J. Kang, and B. Yu, “Gd-doping effect on performance of HfO2 based resistive switching memory devices using implantation approach,” Applied Physics Letters, vol. 98, 2011, p. 042105.
[49] Q. Liu, S. Long, W. Wang, Q. Zuo, S. Zhang, J. Chen, and M. Liu, “Improvement of Resistive Switching Properties in ZrO2-Based ReRAM With Implanted Ti Ions,” IEEE Electron Device Letters, vol. 30, 2009, p. 1335-1337.
[50] C. H. Lin, “Study on the resistive switching characteristics of atomic layer deposition HfO2 with Ti interlayers,” Master thesis, National Tsing Hua University, July 2010.
[51] J. Han, M. Shen, W. Cao, a M. R. Senos, and P. Q. Mantas, “Hopping conduction in Mn-doped ZnO,” Applied Physics Letters, vol. 82, 2003, p. 67.
[52] R. Suzuki, J. Suda, and T. Kimoto, “Temperature Dependence of Electrical Properties of NiO Thin Films for Resistive Random Access Memory,” Materials Research Society, vol. 1071, 2008, p. 4-5.
[53] X. F. Wang, Q. Li, and M. S. Moreno, “Effect of Al and Y incorporation on the structure of HfO2,” Journal of Applied Physics, vol. 104, 2008, p. 093529.
[54] J. Song, A. I. Inamdar, B. Jang, K. Jeon, Y. Kim, K. Jung, Y. Kim, H. Im, W. Jung, H. Kim, and J. P. Hong, “Effects of Ultrathin Al Layer Insertion on Resistive Switching Performance in an Amorphous Aluminum Oxide Resistive Memory,” Applied Physics Express, vol. 3, 2010, p. 091101.
[55] C. Arhammar, C. Moyses Araujo, and R. Ahuja, “Energetics of Al doping and intrinsic defects in monoclinic and cubic zirconia: First-principles calculations,” Physical Review B, vol. 80, 2009, p. 1-9.
[56] H. Zhang, B. Gao, S. Yu, L. Lai, L. Zeng, B. Sun, L. Liu, X. Liu, J. Lu, R. Han, and J. Kang, “Effects of Ionic Doping on the Behaviors of Oxygen Vacancies in HfO2 and ZrO2: A First Principles Study,” 2009 International Conference on Simulation of Semiconductor Processes and Devices, 2009, p. 1-4.
[57] B. Gao, H. W. Zhang, S. Yu, B. Sun, L. F. Liu, X. Y. Liu, Y. Wang, R. Q. Han, J. F. Kang, B. Yu, and Y. Y. Wang, “Oxide-Based RRAM : Uniformity Improvement Using A New Material-Oriented Methodology,” 2009 IEEE Computer Society Annual Symposium on VLSI, 2009, p. 30-31.
[58] A. Makarov, V. Sverdlov, and S. Selberherr, “Stochastic model of the resistive switching mechanism in bipolar resistive random access memory: Monte Carlo simulations,” Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, vol. 29, 2011, p. 01AD03.
[59] Y. J. Wun, “Characterization of Transparent Resistive Random Access Memory Devices Based on HfO2/Al2O3 Multi-layer Stacking as Resistive Switching Film,” Master thesis, National Chiao Tung University, August 2010.
[60] H. B. Lv, H. Wan, and T. Tang, “Improvement of Resistive Switching Uniformity by Introducing a Thin GST Interface Layer,” IEEE Electron Device Letters, vol. 31, 2010, p. 978-980.
[61] W. Y. Chang, K. J. Cheng, J. M. Tsai, H. J. Chen, F. Chen, M. J. Tsai, and T. B. Wu, “Improvement of resistive switching characteristics in TiO2 thin films with embedded Pt nanocrystals,” Applied Physics Letters, vol. 95, 2009, p. 042104.