铁电薄膜底电极La0.5Sr0.5CoO3的结构及电性能研究

采用溶胶-凝胶(Sol-Gel)法在Si衬底上沉积一层La0.5Sr0.5CoO3(LSCO)薄膜底电极,并在不同的退火温度下表征薄膜的各种性质.X线衍射表明在550～750℃退火温度下制备的LSCO薄膜呈(110)取向的钙钛矿结构;谢乐公式估算薄膜的晶粒尺寸为25～50 nm.扫描电子显微镜(SEM)观察结果显示:薄膜表面平整,结构致密.运用四探针法测量薄膜的体电阻,结果表明,750℃退火温度后渗氧处理可获得电阻率较低的La0.5Sr0.5 CoO3薄膜.     

La0.5Sr0.5CoO3薄膜的化学溶液法制备及椭偏光谱研究

用化学溶液沉积法在Si衬底上制备了La0.5Sr0.5CoO 3(LSCO)导电薄膜.X-射线衍射结果表明退火温度600℃可以使LSCO薄膜晶化,薄膜没 有明显的择优取向并呈单一的钙钛矿相.原子力显微镜研究结果表明LSCO薄膜表面平整、无 裂纹及晶粒尺寸较大.用椭偏光谱仪测量了波长300～1700nm范围内LSCO薄膜的椭偏光谱.用适当的拟合模型进行拟合,获得了LSCO 薄膜的光学常数(包括折射率,消光系数,吸收系数等)谱.     

玻璃基LSCO/PZT/LSCO电容器的制备和铁电性能

采用磁控溅射法制备La0.5Sr0.5CoO3(LSCO)薄膜、sol-gel法制备Pb(Zr0.4Ti0.6)O3(PZT)薄膜,在玻璃和Ti-Al/Si衬底上构架了LSCO/PZT/LSCO电容器,研究了衬底对LSCO/PZT/LSCO电容器结构和铁电性能的影响。研究发现:虽然生长在两种衬底上的PZT薄膜均为钙钛矿结构多晶薄膜,但是,生长在玻璃衬底上的LSCO/PZT/LSCO电容器具有更好的铁电性能。玻璃基LSCO/PZT/LSCO电容器的剩余极化强度(Pr)为28×10–6C/cm2,矫顽电压(Vc)为0.96V;而硅基LSCO/PZT/LSCO电容器的Pr为25×10–6C/cm2,Vc为1.05V。     

化学溶液法制备PbZr0.5Ti0.5O3／La0.5Sr0.5CoO3铁电多层薄膜的结构和光学性质研究

采用金属有机化学液相沉积法在Si衬底上制备了La0.Sr0.5CoO3(LSCO)导电金属氧化物薄膜，采用溶胶－凝胶法在LSCO导电金属氧化物薄膜上沉积了PbZr0.5Ti0.5O3（PZT）铁电薄膜，X－射线测量结果表明在700℃的退火温度下制备的PZT／LSCO铁电多层薄膜呈（110）取向的钙钛矿结构，谢乐公式估算铁电薄膜的晶粒尺寸为50－80nm，原子力显微镜观察结果显示：薄膜表面平整，均方根粗糙度（RMS）小于5nm，用拉曼光谱测量表明PZT薄膜呈拉曼活性，椭圆偏振光谱仪用来表征薄膜在400－1700nm波长范围的光学性质，用洛仑兹模型来描述PZT和LSCO薄膜的光学性质，获得PZT和LSCO薄膜的折射率，消光系数等光学常数谱。     

不同衬底温度生长的La_(0.5)Sr_(0.5)CoO_3薄膜椭圆偏振光谱研究

采用脉冲激光沉积法(PLD)在不同Si(100)衬底温度下制备了La_(0.5)Sr_(0.5)CoO_3(LSCO)导电金属氧化物薄膜.X射线衍射(XRD)分析表明,随着衬底温度升高LSCO薄膜的结晶质量增加,在650℃和700℃下制备的薄膜是具有单一钙钛矿结构的多晶薄膜.通过椭圆偏振光谱仪测量了400～1100nm波长范围内该导电金属氧化物薄膜的光学性质,采用双Lorentz振子色散关系及三相结构模型(Air/LSCO/Si)拟合获得了薄膜的光学常数.结果表明,薄膜的折射率随着衬底温度的升高而减小,然而在可见-近红外波长范围内消光系数随着衬底温度的升高而增大.这主要与薄膜的晶化质量和导电性能有密切的关系.     

采用氧化物复合底电极的BTO薄膜结构和性能

用球磨法制备Bi4Ti3O1(2BTO)靶材。用PLD法在Pt/TiO2/SiO2/Si基片上先分别以三种氧化物SrRuO(3SRO)、LaSrCoO3(LSCO)、LaNiO3(LNO)和Pt生成复合底电极,再在其上生长了外延取向的BTO薄膜。分析了薄膜的结构和性能。结果表明,这种BTO薄膜的c轴取向得到抑制,其极化强度从0.45×10–6C/cm2提高到0.9×10–6C/cm2;矫顽场强从90×103V/cm下降到50×103V/cm。     

BST/LSCO异质结构的研究

利用脉冲激光沉积法在STO(001)基片上外延生长了La0.5Sr0.5CoO3(LSCO)导电氧化物薄膜,研究了基片温度对LSCO薄膜结构和电性能的影响,并制备了Ni-Cr/BST/LSCO多层膜结构。XRD谱发现,沉积温度在450~700℃均能得到高度(00 l)取向的LSCO薄膜,LSCO(002)峰的半高峰宽FWHM=0.1°~0.2°;在LSCO薄膜上制备的BST介质膜具有良好的c轴取向和较高的表面平整度,其εr约为470,tgδ为0.036~0.060。     

两步法快速退火对PSTT5铁电薄膜性能的影响

采用射频磁控溅射法在LSCO/Pt/Ti/SiO2/Si(100)衬底上制备了 0.95Pb(Sc0.5Ta0.5)O3-0.05PbTiO3(PSTT5)铁电薄膜.研究了不同的快速退火(RTA)工艺对PSTT5薄膜的结晶性能和铁电性能的影响.实验结果表明,经两步法快速退火,PSTT5薄膜具有完全钙钛矿结构且呈(220)取向.PSTT5薄膜的铁电性能测试结果也表明,采用两步法RTA处理的PSTT5薄膜具有更好的铁电性能,其剩余极化强度(2Pr)可达25.4 μC/cm2.     

Si衬底(Pb1-xSrx)TiO3系铁电薄膜的制备与性能研究

性能优良的 Si衬底铁电薄膜的制备对制作 Si基单片集成非制冷焦平面阵列 (UFPA)器件意义重大。文中采用磁控测射技术在 Si衬底上成功地制备了 (Pb1 - x Srx) Ti O3系铁电薄膜 ,该薄膜以 LSCO/ITO复合薄膜作底电极 ,Au薄膜作顶电极 ,其制备工艺可与 Si微电子技术兼容。测试结果表明 ,其微观结构致密 ,绝缘性较好 ,电阻率可高达 1 0 1 1 Ω· cm量级 ,介电常数与热释电系数分别可达 1 0 2 及 1 0 - 2 μC/cm2 K量级。     

玻璃衬底上RF磁控溅射CIGS薄膜的研究

采用射频磁控溅射的工艺,在玻璃衬底上制备得到了铜铟镓硒(CIGS)薄膜。讨论了衬底温度、溅射气压、退火与否对CIGS薄膜与衬底结合力、显微形貌、晶化程度及电阻率的影响。通过能谱(EDS)测试证明了溅射的CIGS薄膜Ga组分比符合高效吸收层的要求,通过X射线衍射(XRD)与扫描电子显微镜(SEM)测试,证明了衬底加热溅射、溅射后450℃空气退火可以有效提高CIGS薄膜与衬底的结合并提高晶化程度。通过四探针法电阻率测试证明了低气压条件下溅射、溅射后退火可以有效降低CIGS的电阻率,通过透射光谱分析证明了CIGS薄膜对可见光有高吸收效率,适合作为太阳电池的高效吸收层。     

Synthesis of low resistivity complex oxides on MgO using Pt as buffer layer

Highly crystalline SrRuO₃ (SRO) and La_0.5Sr_0.5CoO₃ (LSCO) thin films were deposited on (100) Pt/ MgO by pulsed laser deposition. The films were mainly (001) textured normal to the substrate surface with a high degree of in-plane orientation with respect to the substrate’s major axes. These films were characterized using x-ray diffraction, Rutherford backscattering, four-point probe resistivity measurement, and transmission electron microscopy. The room temperature resistivity for LSCO and SRO films on Pt/MgO was found to be ∼35 and ∼40 μΩ-cm, respectively. An ion beam minimum channeling yield of ∼43% and ∼33% was obtained for LSCO and SRO films, respectively. The interface between Pt and oxide was found to be smooth and free from any interfacial diffusion. This result showed that high-quality low resistivity oxide thin films can be deposited on Pt.     

Structural and Electrical Characters of Ba0.6Sro.4TiO3/La0.5Sr0.5CoO3 Thin Films by Plus Laser Deposition

Epitaxial Ba0.6Sr0.4TiO3 (BST) thin films were deposited on LaAlO3 (LAO) substrates with the conductive metallic oxide La0.5Sr0.5CoO3 (LSCO) film as a bottom electrode by pulsed laser deposition (PLD). Xray relationship of BST/LSCO/LAO was [001] BST//[001]LSCO//[001] LAO. The atomic force microscope (AFM)revealed a smooth and crackfree surface of BST films on LSCOcoated LAO substrate with the average grain size of 120 nm and the RMS of 1.564 nm for BST films.Pt/BST/LSCO capacitor was fabricated to perform CapacitanceVoltage measurement indicating good insulating characteristics. For epitaxial BST film, the dielectric constant and dielectric loss were determined as 471 and 0.03, respectively. The tunabilty was 79.59% and the leakage current was 2.63×107 A/crm2 under an applied filed of 200 kV/cm. Furthermore, it was found that epitaxial BST (60/40) films demonstrate wellbehaved ferroelectric properties with the remnate polarization of 6.085 μC/cm2 and the coercive field of 72 kV/cm. The different electric properties from bulk BST (60/40)materials with intrinsic paraelectric characteristic are attributed to the interface effects.     

（Ba0.5Sr0.5）TiO3铁电薄膜的制备工艺及电学性质研究

采用溶胶 凝胶方法制备出纯立方钙钛矿相、介电性能和漏电流特性良好的 (Ba0 .5Sr0 .5)TiO3 铁电薄膜 .研究发现 ,随着烧结温度的升高 ,(Ba0 .5Sr0 .5)TiO3 薄膜纯度和结晶度增高 ,介电常数提高 ,漏电流密度降低 .在 75 0℃进行保温 1h热处理的薄膜性能较好且稳定 :在室温下测得薄膜介电常数为 2 5 0 ,介电损耗为 0 .0 30 ,漏电流密度为 6 .9× 10 -8A/cm2 .较高的介电常数、较低的漏电流密度可能源于良好的纯度和结晶度 .进一步研究表明 ,薄膜导电遵从空间电荷限制电流机制 .     

Structural and Electrical Characters of Ba0.6Sr0.4TiO3/La0.5Sr0.5CoO3 Thin Films by Plus Laser Deposition

Epitaxial Ba0.6Sr0.4TiO3 (BST) thin films were deposited on LaAlO3 (LAO) substrates with the conductive metallic oxide La0.5Sr0.5CoO3 (LSCO) film as a bottom electrode by pulsed laser deposition (PLD). X-ray diffraction ~2 and Ф scan showed that the epitaxial relationship of BST/LSCO/LAO was [001] BST//[001] LSCO//[001] LAO. The atomic force microscope (AFM) revealed a smooth and crack-free surface of BST films on LSCO-coated LAO substrate with the average grain size of 120 nm and the RMS of 1.564 nm for BST films. Pt/BST/LSCO capacitor was fabricated to perform CapacitanceVoltage measurement indicating good insulating characteristics. For epitaxial BST film, the dielectric constant and dielectric loss were determined as 471 and 0.03, respectively. The tunabilty was 79.59% and the leakage current was 2.6310-7 A/cm2 under an applied filed of 200 kV/cm. Furthermore, it was found that epitaxial BST (60/40) films demonstrate well-behaved ferroelectric properties with the remnate polarization of 6.085 C/cm2 and the coercive field of 72 kV/cm. The different electric properties from bulk BST (60/40) materials with intrinsic paraelectric characteristic are attributed to the interface effects.     

溶胶—凝胶法制备BST铁电薄膜及性能研究

研究了一种以水为溶剂的(Ba