在本實驗中我們成功的製作出了金屬(Al)/鐵電薄膜（PZT）/絕緣層/半導體（p-type）電容器及場效電晶體。絕緣層採用HfO2與ZrO2兩種高介電常數材料，以射頻磁控濺鍍法沈積不同厚度的絕緣層當作緩衝層，經過500oC一分鐘的熱退火處理後，再以射頻磁控濺鍍法沈積PZT，並給予400oC、500oC、600oC與700oC四種不同溫度的熱退火處理。自發性極化的特性是鐵電材料應用於非揮發性記憶體的主要精神，故本實驗主要是藉由電容-電壓以及電流-電壓的量測探討鐵電材料在其中所扮演的角色。
在電容的量測方面，我們發現在PZT經過500oC的熱退火處理可以得到較大的記憶窗，由HfO2當絕緣層的最大的記憶窗達到3.97V，而由ZrO2當絕緣層的最大記憶窗達到3.04V。我們可發現C-V曲線一開始受鐵電極化主導呈現順時針走向，而隨著掃瞄電壓越加越大，電荷注入的影響大於鐵電極化，因此C-V曲線呈現由電荷注入所主導的逆時針走向。在電晶體的量測方面，同樣在PZT經過500oC的熱退火處理可以得到較大的記憶窗。以HfO2當絕緣層的電晶體其次臨界斜率為286mV/decade以及電子遷移率為86cm2/V-sec，已顯現出本電晶體的基本特性，其記憶保持力可達到11.6天，顯示出在記憶保持力部分得到不錯的結果。

Ferroelectric field effect transistors with a metal-ferroelectric- insulator-silicon (MFIS) structure have emerged as promising nonvolatile memory devices. In this work, metal (Al)/ferroelectric (PZT)/insulator/Si MFIS capacitors and field effect transistors using hafnium oxide (HfO2) and zirconium oxide (ZrO2) insulator layers were fabricated. After deposition, the HfO2 and ZrO2 insulator films were first annealed at 500oC and the PZT films were annealed at different temperatures of 400oC, 500oC, 600oC and 700oC. The variation of the memory window as a function of annealing temperature was studied. The maximum capacitance-voltage (C-V) memory window of Al/PZT/HfO2/p-Si capacitors with 500oC-annealed PZT was 3.97V at a sweep voltage of 8V and the similar value for Al/PZT/ZrO2/p-Si capacitors was 3.04V at a sweep voltage of 12V.
The MFIS field effect transistors show normal IDS-VDS and IDS-VGS characteristics. The subthreshold slope of Al/PZT/HfO2/p-Si transistors is 286 mV/decade and the electron mobility is 86 cm2/V-sec. The MFIS transistors with ZrO2 insulator layer show poorer performances. The retention property of MFIS field effect transistors was also measured. The fabricated n-channel MFIS field effect transistors with Al/PZT/HfO2/Si structure exhibited a memory window larger than 0.5V after 11.6 days.

References
[1] T. Sumi and P. D. Maniar, “Ferroelectric nonvolatile memory technology and its applications,” Jpn. J. Appl. Phys., vol. 35, no. 2B, pp. 1516-1520, 1996.
[2] S. L. Miller and P. J. McWhorter, “Physics of the ferroelectric nonvolatile memory field effect transistor,” J. Appl. Phys., vol. 72, no. 12, pp. 5999-6010, 1992.
[3] R. Moazzami, C. Hu, and W.H. Shepherd, “A ferroelectric DRAM cell for high-density NVRAM’s,” IEEE, Electron Device Lett., vol. 11, p. 454 , 1990.
[4] 李雅明, 吳世全, 陳宏名, “鐵電記憶元件”, 電子月刊, 9月號, 1996.
[5] S. Sinharoy, H. Buhay, D. R. Lampe, and M. H. Francombe, “Integration of ferroelectric thin films into nonvolatile memories,” Journal of Vacuum Science & Technology A., vol. 10, no. 4, pp. 1554-1561, 1992.
[6] T. Nakamur and Y. Fujimor, “Fabrication technology of ferroelectric memories,” Jpn. J. Appl. Phys., vol. 37, part. 1, no. 3B, pp. 1325-1327, 1998.
[7] K. H. Kuo and M. J. Sun , “Metal-ferroelectric-semiconductor (MFS) FET’s using LiNbO3/si (100) structures for nonvolatile memory application,” IEEE Electron Device Lett., vol. 19, no. 6, pp. 204-206, 1998.
[8] K. Sugibuchi, Y. Kurogi, and N. Endo, “Ferroelectric field-effect memory device using Bi4Ti3O12 film,” J. Appl. Phys., vol.46, no. 7, pp. 2877-2881, 1975.
[9] N. A. Basit and H. K. Kim, “Growth of highly oriented Pb(Zr,Ti)O3 films on MgO-buffered oxidized si substrates and its application to ferroelectric nonvolatile memory field-effect transistors,” Appl. Phys. Lett., vol. 73, no. 26, pp. 3941-3943, 1998.
[10] H. N. Lee, M. H. Lim, and Y. T. Kim, “Characteristics of metal / ferroelectric / insulator / semiconductor field effect transistors using a Pt/SrBi2Ta2O9 /Y2O3 /Si structure,” Jpn. J. Appl. Phys., vol. 37, part 1, no. 3B, pp. 1107-1109, 1998.
[11] 沈士傑, 徐清祥, “淺談快閃式記憶體(Flash Memory)之發展”, 電子月刊, 9月號, 1996.
[12] H. M. Dulker, P. D. Beal, and J. F. Scott, “Fatigue and switching in ferroelectric memories : theory and experiment,” J. Appl. Phys., vol. 68, pp. 5783-5791, 1990.
[13] J. F. Scott and Y. K. Fang “Device physics of ferroelectric thin-film memories,” Jpn. J. Appl. Phys., vol. 38, part 1, no. 4B, pp. 2272-2274, 1999.
[14] G. W. Dietz, M. Schumacher, and R. Waser, “Leakage current in Ba0.7Sr0.3TiO3 thin films for ultrahigh-density dynamic random access memories,” J. Appl. Phys., vol. 82, no. 5, pp. 2359-2361, 1997.
[15] B. A. Baumert, L. H. Chang, A. T. Matsuda, T. L. Tsai, C. J. Tracy, R. B. Gregory, P. L. Fejes, N. G. Cave, and W. Chen, “Characterization of sputtered barium strontium titanate and strontium titanate thin films,” J. Appl. Phys., vol. 85, no. 2, pp.2558-2566, 1997.
[16] C. M. Wu and F. Y. Chen, “The study of (Ba,Sr)TiO3 thin films deposited on LaNiO3 electrode by RF magnetron sputtering for DRAMs applications,” MSE of NTHU, 1997.
[17] H. Hu and S. B. Ktupanidhi, “Current-voltage characteristics of ultrafine-grained ferroelectric Pb(Zr,Ti)O3 thin film,” J. Mater. Res., vol. 9, no. 6, 1994.
[18] J. F. Scott, C. A. Araujo, B. M. Melnick, and L. D. McMillan, “Quantitative measurement of space-charge effects in lead zirconate-titanate memories,” J. Appl. Phys., vol.70, no. 1, pp. 382-388, 1991.
[19] C. Sudhama, A. C. Campbell, P. D. Maniar, R. E. Jones, R. Moazzami, and C. J. Mogab, “A model for electrical conduction in metal-ferroelectric-metal thin film capacitor,” J. Appl. phys., vol.75, no. 2, pp. 1014-1022, 1994.
[20] N. Inoue and Y. Hayashi, “Effect of imprint on operation and reliability of ferroelectric random acess memory(FeRAM),” IEEE Transactions on Electron Devices, vol. 48, pp. 2266-2272, 2001.
[21] Y. Nakao and Y. Fujisaki, “Study on Pb-based ferroelectric thin films prepared by sol-gel method for memory application,” Jpn. J. Appl. Phys., vol. 33, no. 9B, pp. 5265-5267, 1994.
[22] K. Aoki and Y. Tarui, “Dielectric properties of (111) and (100) lead-zirconate-titanate films prepared by sol-gel technique,” Jpn. J. Appl. Phys. , vol. 33, no. 9B, pp. 5155-5158, 1994.
[23] W. J. Lin and M. Y. Yang, “Growth and fatigue properties of pulsed laser deposited PLZT thin films with [001] preferred orientation,” J. Mat. Sci., vol. 7, pp. 409-417, 1996.
[24] T. F. Tseng, R. P. Yang, and K. S. Liu, “Ferroelectric properties of PLZT films deposited on Si3N4-coated Si substrates by pulsed laser deposition process,” Appl. Phys. Lett., vol. 70, no. 1, pp. 46-48, 1997.
[25] H. Nakasima and Y. Fujimor, “Electrical properties for capacitors of dynamic random access memory on PLZT thin films by metaorganic chemical vapor deposition,” Jpn. J. Appl. Phys., vol. 33, no. 9B, pp. 5139-5142, 1994.
[26] C. M. Foster and H. K. Kim “Single-crystal PZT thin films prepared by metal-organic chemical vapor deposition:systematic compositional variation of electronic and optical properties,” J. Appl. Phys., vol. 81, no. 5, pp. 2349-2357, 1997.
[27] H. Miki and Y. Ohji, “Uniform ultra-thin Pb(Zr,Ti)O3 films formed by metal-organic chemical vapor deposition and their electrical characteristics,” Jpn. J. Appl. Phys., vol. 33, no. 9B, pp. 5143-5146, 1994.
[28] E. Cattan and H. Buhay, “Structure control of PZT buffer layers produced by magnetron sputtering,” Appl. Phys. Lett., vol. 70, no. 13, pp. 1718-1720, 1997.
[29] O. Auciello, A. I. Kingon, and S. B. Krupanidhi, “Sputter synthesis of ferroelectric films and heterostructures,” MAT. RES. BULLETIN, p. 25, 1996.
[30] L. Wang and I. C. Chen, “Properties of PbZrTiO3 thin films preapred by R.F. magnetron sputtering and heat treatment,” Mat. Res. Bull., vol. 25, pp.1495-1501, 1990.
[31] V. Chikarmane and M. H. Francombe, “Effects of post-deposition annealing ambient on the electrical characteristics and phase transformation kinetics of sputtered lead zirconate (65/35) thin film capacitors,” J. Vac. Scl. Technol. A, vol. 10, no. 4, 1992.
[32]T. P. Juan, S. Chen, and Y. M. Lee, “Temperature dependence of the current conduction mechanisms in ferroelectric Pb(Zr0.53,Ti0.47)O3 thin films,” J. Appl. Phys., vol. 95, pp.3121-3125, March 2004.
[33] F. Y. Chen, Y. K. Fang, and M. J. Sun, “Experimental characterization and modeling of a ferroelectric bulk channel field effect transistor with nonvolatile memory characteristics,” Appl. Phys. Lett., vol. 69, pp.812-814, 1996.
[34] Y. Watanabe and M. H. Francombe, “Epitaxial all-perovskite ferroelectric field effect transistor with a memory retention,” Appl. Phys. Lett., vol. 66, pp. 1770-1772, 1995.
[35] K. Nagashima, T. Hirai, H. Koike, Y. Fujisaki, and Y. Tarui, “Characteristics of metal/ferroelectric/insulator/semiconductor structure using SrBi 2Ta 2O 9 as the ferroelectric material,” Jpn. J. Appl. Phys., pt. 1, vol. 35, no. 4B, pp. 1680-1682, 1996.
[36] K. Sugibuchi, Y. Kurogi, and N. Endo, “Ferroelectric field-effect memory device using Bi4Ti3O12 film,” J. Appl. Phys., vol. 46, pp. 2877-2881, November 1975.
[37] H. Sugiyama, T. Nakaiso, Y. Adachi, M. Noda, and M. Okuyama, “An improvement in c-v characteristics of metal/ferroelectric/insulator/semiconductor structure for ferroelectric gate FET memory using a silicon nitride buffer layer,” Jpn. J. Appl. Phys., pt. 1, vol. 38, no. 4B, pp. 2131-2135, 2000.
[38] D. M. Fleetwood et al, IEEE Transactions of Nuclear Science, vol. 39, 1992.
[39] Y. Watanabe and D. R. Lampe, “Energy band diagram of ferroelectric heterostructures and its application to the thermodynamic feasibility of ferroelectric FET,” Solid State Electronics, vol. 108, pp. 59-65, 1998.
[40] 鍾維烈, “鐵電體物理學”, 科學出版社, 1998.
[41] A. Chin, M. Y. Yang, C. L. Sun, and S. Y. Chen, “Stack gate PZT/Al2O3 one transistor ferroelectric memory,” IEEE Electron Device Lett., vol. 22, pp. 336-338, 2001.
[42] G. Yi, Z. Wu, and M. Sayer, “Preparation of Pb(Zr,Ti)O3 thin films by sol gel processing: electrical, optical, and electro-optic properties,” J. Appl. Phys., vol.64, pp. 2717-2724, 1988.
[43] M. P. Moret and M. A. C. Devillers, “Optical properties of PbTiO3, PbZrxTi1-xO3, and PbZrO3 films deposited by metalorganic chemical vapor on SrTiO3,” J. Appl. Phys., vol.92, pp.468-472, 2002.