钛锆酸铅和聚偏氟乙烯共聚物铁电薄膜的制备工艺与电学表征
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摘要
铁电薄膜有着非常广泛的应用,利用铁电薄膜的自发极化取向随外场的方向而发生的变化以及在外场撤去之后的极化保持特性能,可应用于非挥发存储领域,如铁电非挥发薄膜随机存储器件。
首先本文讨论了溶胶凝胶制备钛锆酸铅(PZT)薄膜的工艺,对工艺步骤做出了优化处理,快捷简便地制出高质量的铁电薄膜材料。对制作的PZT薄膜进行了电滞回线、极化保持性能,疲劳等电学性能的测试。通过实验,得出了电畴翻转电流的变化趋势,其中PZT膜的电畴的翻转时间可长达0.2-0.3ms。
利用ALD技术在Pt/SiO2/Si衬底上生长了一层A12O3高介电质常数介质材料,并在上面利用溶胶-凝胶法制备了PZT铁电薄膜。在对PZT/Al2O3双层膜的电学性能测试中,发现了高k介质层对PZT薄膜的疲劳、保持特性等都有所改进。通过对双层膜电滞回线和XRD衍射峰的分析,确认了Al2O3对PZT晶体生长的促进作用。
偏氟乙烯聚合物(P(VDF-TrFE))是一种应用十分广泛的有机铁电材料。本文采用溶液匀胶法制备了P(VDF-TrFE)(70:30)薄膜。对其制备工艺进行了研究。通过XRD图,确定其晶相,之后测试了薄膜的电滞回线、疲劳、保持、电容-电压(C-V)特性。通过对不同电极薄膜的电滞回线的对比,发现电极与薄膜之间形成了一层界面层,该界面层对薄膜的铁电性能产生了负面的影响。本文通过引入PSSH有机膜作为缓冲层,将电极和铁电层隔开,使得电极与薄膜不能直接接触,抑制了界面反应,改善了P(VDF-TrFE)膜的疲劳及保持特性。
我们还通过SPM技术测量了P(VDF-TrFE)膜的压电特性。测量了退火前后的薄膜表面形貌的差别。通过压电回线研究了P(VDF-TrFE)单畴翻转的过程,并解释了通过压电回线所得到的矫顽场低于宏观电学测量的矫顽场的原因。
Ferroelectric materials have been widely used because of their unique properties. The ferroelectric polarization can be switched in a different direction to store the logic information for the memories.
PZT thin films were prepared via Sol-gel method. Polarization-electric(P-E) hysteresis loops, retention, and fatigue were measured. The switching process of PZT was studied. By varyig doamain switching currents,we understand the kinetics of PZT domain switching.
High-k Al2O3 layer was deposited through ALD method on Pt/SiO2 substrates. After that, the PZT film was grown on their top.Ultrathin ferroelectric films could suffer from bad polarization retention due to epitaxial stresses and interfacial effects. However, thing changes, once ultrathin PZT films are incorporated with a few nanometer-thick Al2O3.The ferroelectric properties, such as fatigue and retention, show obvious improvements in our experiment. The ultra-thin Al2O3 layer which acts as a tunnel switch in the progress of domain switching affects ferroelectric properties in many ways.
Poly(vinylidene fluoride) (PVDF) is one of the most widely used polymer materials, due to its good piezoelectricity and piezoelectricity. Nowadays, PVDF thin films have been paid more and more attentions in material science. In this work, P(VDF-TrFE)(70:30) films were prepared by cast coating method. Consequently, ferroelectric properties of P(VDF-TrFE)/PSSH were studied.
The topography of the film surface was measured through SPM, and the ferroelectricity was studied through piezo-response characterization. The derived the coercive voltage through a piezo response is lower than that obtained from a P-E hysteresis loop in a large capacitor.
首先本文讨论了溶胶凝胶制备钛锆酸铅(PZT)薄膜的工艺,对工艺步骤做出了优化处理,快捷简便地制出高质量的铁电薄膜材料。对制作的PZT薄膜进行了电滞回线、极化保持性能,疲劳等电学性能的测试。通过实验,得出了电畴翻转电流的变化趋势,其中PZT膜的电畴的翻转时间可长达0.2-0.3ms。
利用ALD技术在Pt/SiO2/Si衬底上生长了一层A12O3高介电质常数介质材料,并在上面利用溶胶-凝胶法制备了PZT铁电薄膜。在对PZT/Al2O3双层膜的电学性能测试中,发现了高k介质层对PZT薄膜的疲劳、保持特性等都有所改进。通过对双层膜电滞回线和XRD衍射峰的分析,确认了Al2O3对PZT晶体生长的促进作用。
偏氟乙烯聚合物(P(VDF-TrFE))是一种应用十分广泛的有机铁电材料。本文采用溶液匀胶法制备了P(VDF-TrFE)(70:30)薄膜。对其制备工艺进行了研究。通过XRD图,确定其晶相,之后测试了薄膜的电滞回线、疲劳、保持、电容-电压(C-V)特性。通过对不同电极薄膜的电滞回线的对比,发现电极与薄膜之间形成了一层界面层,该界面层对薄膜的铁电性能产生了负面的影响。本文通过引入PSSH有机膜作为缓冲层,将电极和铁电层隔开,使得电极与薄膜不能直接接触,抑制了界面反应,改善了P(VDF-TrFE)膜的疲劳及保持特性。
我们还通过SPM技术测量了P(VDF-TrFE)膜的压电特性。测量了退火前后的薄膜表面形貌的差别。通过压电回线研究了P(VDF-TrFE)单畴翻转的过程,并解释了通过压电回线所得到的矫顽场低于宏观电学测量的矫顽场的原因。
Ferroelectric materials have been widely used because of their unique properties. The ferroelectric polarization can be switched in a different direction to store the logic information for the memories.
PZT thin films were prepared via Sol-gel method. Polarization-electric(P-E) hysteresis loops, retention, and fatigue were measured. The switching process of PZT was studied. By varyig doamain switching currents,we understand the kinetics of PZT domain switching.
High-k Al2O3 layer was deposited through ALD method on Pt/SiO2 substrates. After that, the PZT film was grown on their top.Ultrathin ferroelectric films could suffer from bad polarization retention due to epitaxial stresses and interfacial effects. However, thing changes, once ultrathin PZT films are incorporated with a few nanometer-thick Al2O3.The ferroelectric properties, such as fatigue and retention, show obvious improvements in our experiment. The ultra-thin Al2O3 layer which acts as a tunnel switch in the progress of domain switching affects ferroelectric properties in many ways.
Poly(vinylidene fluoride) (PVDF) is one of the most widely used polymer materials, due to its good piezoelectricity and piezoelectricity. Nowadays, PVDF thin films have been paid more and more attentions in material science. In this work, P(VDF-TrFE)(70:30) films were prepared by cast coating method. Consequently, ferroelectric properties of P(VDF-TrFE)/PSSH were studied.
The topography of the film surface was measured through SPM, and the ferroelectricity was studied through piezo-response characterization. The derived the coercive voltage through a piezo response is lower than that obtained from a P-E hysteresis loop in a large capacitor.
引文
[1]钟维烈,铁电物理学[M],科学出版社,北京,1996.
[2]刘梅冬,许毓春,压电铁电材料与器件[M],武汉：华中理工大学出版社,1990.
[3]A.W. Heeat, Solid State J. Phys.2559,1973
[4]李金桂,肖定全等,现代表面工程设计手册,国防工业出版社,2000,12-27
[5]罗维根,丁爱丽,不挥发铁电存储器的最新发展[M],无机材料学报,Vol.11,no.1,1996.
[6]J. F. Scott, C. A.Paz de Araujo, L. D. McMillan et al.Ferroelectric Thin Films in Integrated Microelectronic Devices[J].Ferroelectrics,1992,133:47-50.
[7]J. R. Anderson, "Ferroelectric storage elements for digital computers and switching system" [J], Electr. Engineering,1952,71:916-920.
[8]S. L. Miller, R. D. Nasby, J. R. Schwank et al. Device modeling of ferroelectric capacitors[J]. J. Appl. Phys.1990,68(12):6463-6471.
[9]]B. Jafffe, W. R. Cook Jr,H. Jaffe. Piezoelectric Ceramics[J].New York:Academic Press, 1971.
[10]Kittel C. Theory of Antiferroelectric Crystals [J].Phys. Rev.,1951,82:7292732.
[11PROCEEDINGS OF THE IEEE, VOL.88, NO.5, MAY 2000
[12]Eaton,S.S,, Butler,D.B., Parris,M., Wilson,D., McNeille.H., IEEE Intern. Solid State Circuits Conf. Digest of Technical Papers, p.130(1988)
[13]FED Journal Vol.11 Supplement (2000)
[14]Ross,I.M:US Patent No.2791760 (1957)
[15]W. Kinney, "Signal magnitudes in high density ferroelectric memories," Integrat. Ferroelect, vol.4, pp.131-144,1994.
[16]R. G.Kepler, R. A. Anderson, Adv. Phys. Lete.,58,36(1991).
[17]B. A. Newman, J.I. Sheinbein, J. W. Lee, Y. Takase, Ferroelectrics,127, 229(1992); B. Z. Mei, J.I.Scheinbeim, B.A.Newman, Ferroelectrics,144,51(1993)
[18]J. F. Legrand, Ferroelectrics,91,303(1989).
[19]Furukawa, T, Structure and functional properties of ferroelectric polymers. Advances in colloid and interface science,1997.71-72:p.183-208.
[20]Kepler, R.G, Ferroelectric, pyroelectric, and piezoelectric properties of poly (vinylidene fluoride), in Sandia National Laboratories:Albuquerque, New Mexico.
[21].范雄,金属X射线学,机械工业出版社,1998
[22]何崇智,X射线衍射实验技术,上海科技出版社,1988
[23]朱国栋博士论文[D],上海,复旦大学材料系.
[24]付海涛博士论文[D],上海,复旦大学材料系
[25]郭琳,刘会,铁电材料研究的背景及现状分析,重庆大学学报,2007,26：1-3
[26]Markku Leskela*,Mikko Ritala, Atomic layer deposition (ALD):from precursors to thin film structures,2002,409:138-146
[27]A.Q. Jiang, Y.Y. Lin, and T.A. Tang, J. Appl. Phys.101,56103 (2007).
[28]A.Q. Jiang, Y.Y. Lin, and T.A. Tang:Evaluation of interfacial-layer capacitance from fast polarization retention in ferroelectric thin films. J. Appl. Phys.2007; 101:56103.
[29]L.J. Sinnamon, M.M. Saad, R.M. Bowman, and J.M. Gregg:Exploring grain size as a cause for "dead layer" effects in thin film capacitors. Appl. Phys. Lett.2002; 81:703-705.
[30]V. Nagarajan, et al.:Dynamics of ferroelectric domains in ferroelectric thin films. Nature Materials.2003;2:43-47.
[31]J.Y. Jo, Y.S. Kim, T.W. Noh, J.-G. Yoon, and T.K. Song:Coercive fields in ultrathin BsTiO3 capacitors. Appl. Phys. Lett.2006; 89:232909.
[2]刘梅冬,许毓春,压电铁电材料与器件[M],武汉：华中理工大学出版社,1990.
[3]A.W. Heeat, Solid State J. Phys.2559,1973
[4]李金桂,肖定全等,现代表面工程设计手册,国防工业出版社,2000,12-27
[5]罗维根,丁爱丽,不挥发铁电存储器的最新发展[M],无机材料学报,Vol.11,no.1,1996.
[6]J. F. Scott, C. A.Paz de Araujo, L. D. McMillan et al.Ferroelectric Thin Films in Integrated Microelectronic Devices[J].Ferroelectrics,1992,133:47-50.
[7]J. R. Anderson, "Ferroelectric storage elements for digital computers and switching system" [J], Electr. Engineering,1952,71:916-920.
[8]S. L. Miller, R. D. Nasby, J. R. Schwank et al. Device modeling of ferroelectric capacitors[J]. J. Appl. Phys.1990,68(12):6463-6471.
[9]]B. Jafffe, W. R. Cook Jr,H. Jaffe. Piezoelectric Ceramics[J].New York:Academic Press, 1971.
[10]Kittel C. Theory of Antiferroelectric Crystals [J].Phys. Rev.,1951,82:7292732.
[11PROCEEDINGS OF THE IEEE, VOL.88, NO.5, MAY 2000
[12]Eaton,S.S,, Butler,D.B., Parris,M., Wilson,D., McNeille.H., IEEE Intern. Solid State Circuits Conf. Digest of Technical Papers, p.130(1988)
[13]FED Journal Vol.11 Supplement (2000)
[14]Ross,I.M:US Patent No.2791760 (1957)
[15]W. Kinney, "Signal magnitudes in high density ferroelectric memories," Integrat. Ferroelect, vol.4, pp.131-144,1994.
[16]R. G.Kepler, R. A. Anderson, Adv. Phys. Lete.,58,36(1991).
[17]B. A. Newman, J.I. Sheinbein, J. W. Lee, Y. Takase, Ferroelectrics,127, 229(1992); B. Z. Mei, J.I.Scheinbeim, B.A.Newman, Ferroelectrics,144,51(1993)
[18]J. F. Legrand, Ferroelectrics,91,303(1989).
[19]Furukawa, T, Structure and functional properties of ferroelectric polymers. Advances in colloid and interface science,1997.71-72:p.183-208.
[20]Kepler, R.G, Ferroelectric, pyroelectric, and piezoelectric properties of poly (vinylidene fluoride), in Sandia National Laboratories:Albuquerque, New Mexico.
[21].范雄,金属X射线学,机械工业出版社,1998
[22]何崇智,X射线衍射实验技术,上海科技出版社,1988
[23]朱国栋博士论文[D],上海,复旦大学材料系.
[24]付海涛博士论文[D],上海,复旦大学材料系
[25]郭琳,刘会,铁电材料研究的背景及现状分析,重庆大学学报,2007,26：1-3
[26]Markku Leskela*,Mikko Ritala, Atomic layer deposition (ALD):from precursors to thin film structures,2002,409:138-146
[27]A.Q. Jiang, Y.Y. Lin, and T.A. Tang, J. Appl. Phys.101,56103 (2007).
[28]A.Q. Jiang, Y.Y. Lin, and T.A. Tang:Evaluation of interfacial-layer capacitance from fast polarization retention in ferroelectric thin films. J. Appl. Phys.2007; 101:56103.
[29]L.J. Sinnamon, M.M. Saad, R.M. Bowman, and J.M. Gregg:Exploring grain size as a cause for "dead layer" effects in thin film capacitors. Appl. Phys. Lett.2002; 81:703-705.
[30]V. Nagarajan, et al.:Dynamics of ferroelectric domains in ferroelectric thin films. Nature Materials.2003;2:43-47.
[31]J.Y. Jo, Y.S. Kim, T.W. Noh, J.-G. Yoon, and T.K. Song:Coercive fields in ultrathin BsTiO3 capacitors. Appl. Phys. Lett.2006; 89:232909.