溶胶-凝胶法制备PZT铁电薄膜的结构特征研究

采用溶胶－凝胶方法在Pt／Ti／SiO2／Si衬底上制备了光滑均匀的PZT（50／50）铁电薄膜。用XRD、FT－IR反射光谱、Raman光谱以及原子力显微镜（AFM）研究了薄膜随热处理温度的结构变化过程以及薄膜中有机物的挥发。Raman光谱给出了薄膜中三方和四方相共存及转变的结构变化信息。AFM揭示了PZT薄膜中钙铁矿相的形成是从焦绿石结构中转变而来的，其生长机制可用Rosettes生长模型来解释。薄膜中相交约120°交角的3条延伸的界面线则是为了释放薄膜中的应力而产生的。     

LaNiO3缓冲层对Pb(Zr,Ti)O3铁电薄膜的影响

采用化学溶液法在Pt／Ti／SiO2／Si衬底上制备了PbZr0．4Ti0.6O3／LaNiO3(PZT／LNO)多层薄膜。X射线衍射测量表明LNO缓冲层的引入使PZT薄膜(111)择优取向度减小,(100)取向增加。原子力显微镜测量表明引入LNO缓冲层使得PZT薄膜表面更加平整、致密。在LNO缓冲层上制备的PZT薄膜具有优良的铁电特性和介电特性：LNO缓冲层厚度为40nm时,500kV／cm的外加电．场下。剩余极化(Pr)为37．6μC／cm^2,矫顽电场(Ec)为65kV／cm;100kHz时,介电常数达到822,并且发现LNO缓冲层的厚度为40nm,PZT的铁电、介电特性改进最为显著。     

沉积在Pt电极上的铁电PZT薄膜特性

研究了射频磁控溅射沉积在Pt电极上的Pb（Zr0．53Ti0．47）O3薄膜特性。经过不同温度退火处理后得到了钙钛矿结构的PZT薄膜。在对其结构的形成和变化进行研究的基础上，探讨了薄膜PZT相的形成机理。其电性能的测试表明，这种铁电PZT（53／47）薄膜具有较好的铁电性能和疲劳特性。在600℃下PZT薄膜的剩余极化强度Pr为24．8μC／cm2，矫顽场强度Ec为70kV／cm。210kV／cm的电场下，疲劳循环直到4×108次时，最大极化强度仍有20．6μC／cm2，降低了约34％，其剩余极化强度保持为10μC／cm2左右。     

Sol-gel法制备Pb(Zr0.53Ti0.47)O3铁电薄膜

利用Sol-gel工艺在Pt/Ti/SiO2/Si衬底上制备了Pb(Zr0.53Ti0.47)O3(PZT)薄膜,研究了退火温度、保温时间和薄膜厚度对其晶相、微观结构和铁电性能的影响.在500℃退火处理的PZT薄膜开始形成钙钛矿相;在550℃退火处理的PZT薄膜基本形成钙钛矿相结构;升高退火温度(500～850℃)、延长保温时间(30～150min)、增加薄膜厚度(120～630nm)都有利于PZT晶粒的长大.在650～750℃退火的PZT薄膜具有较好的铁电性能,保温时间对PZT薄膜的铁电性能影响不大,PZT薄膜的厚度为200～300nm时可以得到比较好的铁电性能.在退火温度750℃、保温时间30min条件下退火处理厚310nm的PZT薄膜,其剩余极化值(2Pr)和矫顽电场(2Ec)分别是72μC/cm2、158kV/cm.     

电极对PZT铁电薄膜的微观结构和电性能的影响

采用溶胶—凝胶(sol—gel)工艺分别在Pt／Ti／SiO2／Si和LNO／Si电极上制备Pb(Zr0．53，Ti0．47)O3(PZT)铁电薄膜。研究了不同电极材料对PZT铁电薄膜的微结构及电性能的影响。(100)择优取向的PZT／LNO薄膜的介电性能和铁电性能较(111)／(100)取向的PZT／Pt薄膜略有下降，但在抗疲劳特性和漏电流特性方面都有了很大提高。PZT／LNO薄膜10m次极化反转后剩余极化几乎保持未变，直至10^12次反转后，剩余极化仅下降了17％。     

PZT薄膜的MOCVD制备技术

采用直接液体榆运-金属有机化合物化学气相沉积技术（DLI-MOCVD）制备Pb（ZrxTi1-x）O3薄膜（PZT薄膜）,并进行了相关研究,通过调节MOCVD中影响PZT质量的主要工艺参数（温度、压力、系统的气体（Ar,O2）流量、衬底转速、蠕动泵速）,制备不同组分PZT薄膜（均匀性≥±95％,尺寸为2．54—20．32cm（1—8in）,厚度为50—500nm）．经XRD测试可见,PZT薄膜已形成钙钛矿结构．用SEM对其表面进行分析,结果表明,PZT薄膜表面致密均匀．     

掺锡氧化铟基底上锆钛酸铅铁电薄膜的制备与表征

用溶胶-凝胶工艺在掺锡氧化铟导电氧化物基底上制备了锆钛酸铅（PZT）铁电薄膜．采用快速热处理工艺改进铁电薄膜的晶格取向，用X射线衍射仪分析了薄膜的结晶取向，分别基于Al／PZT／ITO，1TO／PZT／1TO电容结构利用Sawyer-Tower电路原理测试了薄膜的铁电性能．结果表明，在磁控溅射法生长的1TO表面能够制备出具有钙钛矿结构的（110）取向的PZT铁电薄膜，所得薄膜的相对介电常数达到1000，剩余极化强度Pr达到和Pt基底上接近的15．2uc／cm^2，矫顽场强Ec达到70．8kV/cm．并且利用TF Analyzer 2000铁电分析仪测试了PZT铁电薄膜的疲劳特性，发现ITO底电极上PZT薄膜经过108次反转后，剩余极化强度仅下降15％．研究表明：磁控溅射法制备的掺锡氧化铟透明导电薄膜ITO可以作为铁电薄膜的上下电极．     

退火温度对BZT薄膜介电性能的影响研究

采用sol-gel法在Pt/Ti/SiO2/Si衬底上制备了Ba(Zr0.2Ti0.8)O3(BZT)薄膜。X射线衍射分析表明,该BZT薄膜为钙钛矿结构而无其它物相存在。光学显微镜分析结果表明,退火温度为900℃时,BZT薄膜表面光滑平整,无裂纹产生;同时其介电常数最大而损耗最低。     

不同晶化处理方式对PZT薄膜性能的影响

采用改进的溶胶一凝胶（sol—gel）法在Pt／Ti／SiO2／Si基片上制备PZT薄膜,研究不同的晶化处理方式对PZT薄膜的微观结构、表面形貌及电学性能的影响。实验结果表明：快速晶化处理方式更有利于薄膜沿（110）方向的择优生长;并且相对于常规晶化处理方式,快速晶化处理方式制备的PZT薄膜晶粒均匀,排布有序,可有效的提高薄膜的表面质量。电学性能测试结果表明,这种表面形貌可以有效地降低漏电流。     

不同衬底上LaNiO3导电氧化物薄膜的制备和研究

通过MOD法和快速热处理过程,在Si(100)和Pt(111)/Ti/SiO2/Si衬底上制备了LaNiO3(LNO)导电氧化物薄膜.经XRD结构分析表明,所制备的LNO薄膜具有纯的钙钛矿结构,并且以(100)方向择优取向.经SEM和AFM分析表明,LNO薄膜具有表面均匀、无裂纹.经标准四探针法测试表明,LNO薄膜具有好的金属特性,其室温电阻率为7.6×10-4Ω·cm.铁电性能测试表明,LNO薄膜可以提高PZT铁电薄膜的剩余极化强度.     

Effect of microwave annealing temperatures on lead zirconate titanate thin films

Lead zirconate titanate (Pb(1.1)(Zr(0.52)Ti(0.48))O(3)) thin films of thickness 260?nm on Pt/Ti/SiO(2)/Si substrates were densified by 2.45?GHz microwave annealing. The PZT thin films were annealed at various annealing temperatures from 400 to 700?°C for 30?min. X-ray diffraction showed that the pyrochlore phase was transformed to the perovskite phase at 450?°C and the film was fully crystallized. The secondary (again pyrochlore) phase was observed in the PZT thin films, which were annealed above 550?°C. The surface morphologies were changed above 550?°C of the PZT thin films due to the secondary phase. Higher dielectric constant (ε(r)) and lower dielectric loss coercive field (E(c)) were achieved for the 450?°C film than for the other annealed films.     

Dielectric properties of lead zirconate titanate thin films seeded with barium strontium titanate nanoparticles

A low temperature synthetic method recently proposed by the authors was applied to the fabrication of lead zirconate titanate (PZT) thin films containing crystalline seeds of barium strontium titanate (BST) nanoparticles. PZT precursor and the BST particles were prepared with complex alkoxide methods. Precursor solution suspending the BST particles was spin-coated on Pt/Ti/SiO₂/Si substrate to film thickness of 500–800 nm at particle concentrations of 0–25.1 mol%, and annealed at various temperatures. Seeding of BST particles prevented the formation of pyrochlore phases, which appeared at temperatures above 400 °C in unseeded PZT films, and induced crystallization of PZT into perovskite structures at 420 °C, which was more than 100 °C below the crystallization temperature of the unseeded PZT films. Measurement of dielectric properties at 1 kHz showed that the 25.1 mol% BST-seeded PZT films annealed at 450 °C had a dielectric constant as high as 300 with a dissipation factor of 0.05. Leakage current density of the film was less than 1×10⁻⁶ A/cm² at applied electric field from 0 to 64 kV/cm.     

PZT thin film preparation by pulsed DC magnetron sputtering

Pulsed DC magnetron sputtering was used in this study to prepare lead zirconate titanate (Pb(Zr_xTi_1−x)O₃, PZT) thin films. A single metallic target was used for the deposition onto a Pt/Ti/SiO₂/Si substrate and parameters such as: pulse frequency, duty cycle, O₂/Ar flow ratio controlled so as to analyze the effect of the parameters on thin film deposition rate, crystalline structure and morphology. After the deposition, the thin film was annealed in a rapid thermal annealing (RTA) furnace. The experimental results showed that, when the pulse frequency was in the range of 10 kHz-100 kHz, along with the lowering of frequency and the oxygen argon flow rate ratio, the deposition rate gradually increased and the formation of PZT thin film perovskite phase was enhanced; however, if the oxygen argon flow rate ratio was too high, it caused the PZT thin film to generate a pyrochlore phase. However, when the duty cycle was in the range of 95%-75%, the highest deposition rate and better perovskite phase could be obtained in the range of 75%-80%.     

Crystallization behavior and domain structure in textured Pb(Zr0.52Ti0.48)O3 thin films by different annealing processes

Amorphous Pb(Zr_0.52Ti_0.48)O₃ (PZT) thin films were prepared on the Pt/Ti/SiO₂/Si substrates by radio-frequency magnetron sputtering at room temperature. After rapid thermal annealing (RTA) and conventional furnace annealing (CFA) at different temperatures, the films were transformed into polycrystalline PZT thin films with (111) and (100) orientation, respectively. The phase formation and ferroelectric domains correlated with different orientation were systematically investigated by X-ray diffraction and piezoresponse force microscopy. The results showed that the perovskite PZT crystal with [111] orientation hetero-nucleated preferentially on top of the PtPb intermetallic phase at the PZT/Pt interface during RTA process. It is of interest to find that the domain self-organized into a structure with rounded shape at the early stage of crystallization. While the nucleation of the films treated by CFA dominantly homo-nucleated, thus the (100) orientation grains with minimum surface energy were easy to grow. The texture effects on ferroelectric properties of PZT films were also discussed in relation to the domain structure.     

退火时间对BNT-BT6薄膜微结构及压电性能的影响

采用溶胶-凝胶法(Sol-Gel)在Pt/Ti/SiO2/Si(100)衬底上制备了0.94(Na0.5Bi0.5)TiO3-0.06BaTiO3(BNT-BT6)薄膜,研究了不同退火时间对其微结构和压电性能的影响。X射线衍射(XRD)结果表明,制备的BNTBT6薄膜为钙钛矿型铁电薄膜,随着退火时间的延长,晶粒尺寸略有增加。原子力显微镜(AFM)结果表明,制备的薄膜表面比较平整、无裂缝。随着退火时间的延长,薄膜的粗糙度有所增加。在退火时长为60min时薄膜表面具有最佳的均一性,在退火时间为90min时薄膜均一性最差;优化退火时间,可提高薄膜结晶程度,避免焦绿石相的生成,进而提高BNT-BT6薄膜压电性能。压电力显微镜(PFM)结果表明,BNT-BT6薄膜的电畴为多畴结构。在不同退火时间下均有明显的压电响应,特别是在退火时间为60min时,BNT-BT6原始电畴有着最高的振幅强度。在30min、40min、60min和90min退火时间时,其平均压电系数d33分别为48pm/V、157pm/V、186pm/V和142pm/V。     

Distribution of pyrochlore phase in Pb(Mg1/3Nb2/3)O3-PbTiO3 films and suppression with a Pb(Zr0.52Ti0.48)O3 interfacial layer

Thin films of the relaxor ferroelectric Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) on Pt/Ti/SiO₂/Si (Pt/Si) substrates both with and without a Pb(Zr_0.52Ti_0.48)O₃ (PZT) interfacial layer were investigated. Perovskite and pyrochlore coexistence was observed for PMN-PT thin films without a PZT interfacial layer. Interestingly, most of the pyrochlore phase was observed in single-coated films and in the first layer of multi-coated films. The pyrochlore phase exhibited grains with an average size of about 25 nm, which is smaller than those of the perovskite phase (about 90 nm). In contrast, for PMN-PT thin films grown on a PZT interfacial layer, the formation of a pyrochlore phase at the interface between PMN-PT layers and the substrate is completely suppressed. Moreover, small grains are not observed in the films with a PZT interfacial layer. The measured polarization-electric field (P-E) hysteresis loops of PMN-PT films with and without PZT layers indicate that enhanced electrical properties can be obtained when a PZT interfacial layer is used. These enhanced properties include an increase in the value of remanent polarization P_r from 2.7 to 5.8 μC/cm² and a decrease in the coercive field E_c from 60.5 to 28.0 kV/cm.     

RF sputtered PLZT thin film on Pt/Ti electrode

PLZT (7.5/65/35) thin films were deposited by rf magnetron sputtering on single crystal Si substrates using an oxide sintered target with excess PbO. The effects of postannealing and bottom Pt/Ti electrodes on the thin film crystal structures and ferroelectric properties were studied. Film deposited at 200°C or below crystallizes to a perovskite phase after annealing treatment at 550°C or above, and the crystal structure depends on the annealing treatment. The best crystal structures and electronic properties were obtained when the thin films were annealed at 600°C to 650°C for 1 h in O₂. For the Pt/Ti two-layer bottom electrode, the thickness of the Ti layer has a dominant effect. When the Ti layer was too thick or too thin, the PLZT thin film structures consist mainly of pyrochlore phases. However, using an appropriate Ti layer thickness, PLZT thin films having good crystal structures and ferroelectric properties can be obtained, with typical remanent polarization value of 220 mC/m² and coercive field strength of 6.5 MV/m     

Microstructural and electrical properties in textured lead calcium lanthanum titanate thin films deposited on a Pt/Ti/SiO2/Si substrate

Textured Ca modified (Pb,La)TiO₃ (PLCT) films were deposited on Pt/Ti/SiO₂/Si substrates using a metal-organic decomposition (MOD) process. The microstructure of the PLCT thin film was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Electric properties were measured using the Pt/PLCT/Pt capacitor structure. The PLCT films exhibit good ferroelectric and dielectric properties.     

Effects of a PbTiO3 insertion layer on the morphological and electromechanical characteristics of sol-gel-driven 0.2PZN-0.8PZT piezoelectric films for energy harvesters

This study investigated the morphological and electromechanical characteristics of 0.2PZN-0.8PZT films fabricated using a PbTiO3 layer. Crack-free 1-microm-thick films with a pure perovskite phase were obtained on Pt/Ti/SiO2/Si substrates using a modified sol-gel deposition method. A highly dense and smooth morphology and a high piezoelectric coefficient (d33) of 230 pC/N were observed in a 0.2PZN-0.8PZT film with a PbTiO3 insertion layer after annealing at 750 degrees C. The as-produced sol-gel-driven 0.2PZN-0.8PZT thin films are attractive for application to piezoelectrically operated microelectronic actuators, sensors, or energy harvesters due to their low facility cost, smooth surface, and excellent electromechanical characteristics.     

溅射工艺参数对PZT铁电薄膜相变过程的影响

采用射频磁控溅射工艺,在（１１１）Ｐｔ／Ｔｉ／ＳｉＯ２／Ｓｉ衬底上用ＰＺＴ（５３／４７）陶瓷靶制备铁电薄膜。用快速光热退火炉对原位沉积的薄膜进行ＲＴＡ处理。