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The ferroelectric properties of Nb-doped PZT thin films prepared by a sol-gel method were evaluated relative to memory device
application requirements. Within the range of 0 to 4 mol %, Nb-doping of PZT compositions near the morphotropic phase boundary
region (i.e. PZT 53/47) enhanced overall ferroelectric properties by reducing the te-tragonal distortion of the unit cell. A 4 mol % Nb-doped
PZT 53/47 thin film (0.26 μm) had a coercivity of 8 V/ μm, a remanence ratio of 0.54, a switchable polarization of 45 μC/cm2, and a specific resistivity of 3 x 109 Ω-cm. Nb-doping levels in excess of 5 mol had a detrimental effect on the resulting thin film ferroelectric properties. X-ray
diffraction (XRD) analysis of highly doped films showed development of a significant PbO phase accompanied by diffraction
line broadening of the perovskite phase. As such, it was postulated that the creation of excessive lead vacancies in the PNZT
lattice resulted in PbO accumulation at the grain boundaries which impeded grain growth, and hence, adversely affected ferroelectric
switching performance. The fatigue performance of the sol-gel derived thin film capacitor system was a function of switching
voltage. At switching fields sufficient to saturate the polarization, the endurance of the thin film capacitor was greater
than 109 cycles. Cycling with lower fields reduced endurance values, but in all cases, the switchable polarization decreased linearly
with the logarithm of cycles. Nb-doping did not have a significant effect on the fatigue performance. 相似文献
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用磁控溅射法在Pt/Ti/SiO2 /Si衬底上制备了PbZr0 .52 Ti0 .4 8O3(PZT)薄膜 .XRD结果表明经过退火后的PZT薄膜呈现多晶结构 .通过红外椭圆偏振光谱仪测量了λ为 2 .5~ 12 .6 μm范围内PZT薄膜的椭偏光谱 ,采用经典色散模型拟合获得PZT薄膜的红外光学常数 ,同时拟合得到未经处理的PZT薄膜和退火后PZT薄膜的厚度分别为 45 4.2nm和 45 0 .3nm .最后通过拟合计算得到结晶PZT薄膜的静态电荷值为 |q|=1.76 9± 0 .0 2 4.这说明在磁控溅射法制备的PZT薄膜中 ,电荷的转移是不完全的 . 相似文献
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电极对PZT铁电薄膜性能的影响 总被引:8,自引:1,他引:7
用溶胶-凝胶法制备PZT铁电薄膜。以Pt/Ti/SiO2/Si为底电极,Au为上电极,形成金属-铁电薄膜-金属结构的铁电电容器。研究电极对PZT铁电薄膜结构和电性能的影响,实验发现,金属Ti的厚度会影响PZT铁电薄膜的结构。界面层的存在使介电系数、自发极化、矫顽电压、漏电流都与薄膜的厚度有关。 相似文献
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采用sol-gel(溶胶-凝胶)法在Pt/Ti/SiO2/Si基底上分别制备了厚度为400nm,600nm,800nm的PZT(锆钛酸铅,Zr/Ti=52/48)薄膜,研究了厚度对薄膜介电性能与铁电性能的影响。通过对薄膜的铁电性能与介电性能进行测试,分析了不同厚度薄膜的剩余极化强度、介电常数与介电损耗;通过对介电调谐率与最大正切损耗的计算,进一步分析了薄膜的介电调谐性能。实验结果表明,薄膜的介电常数与介电损耗随薄膜厚度的增大而增加;厚度为600nm的薄膜具有最好的介电调谐性能与铁电性能。 相似文献
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Bi_(3.5)Yb_(0.5)Ti_3O_(12)铁电薄膜的制备及性能 总被引:1,自引:0,他引:1
采用溶胶-凝胶(Sol-Gel)法在Pt(111)/Ti/SiO2/Si(100)基片上淀积了Bi3.5Yb0.5Ti3O12(BYT)铁电薄膜,研究了在不同退火温度下形成的BYT薄膜的微观结构以及铁电性能方面的区别。结果发现,在610,660,710和760℃不同温度下退火的BYT薄膜的结晶度不同,退火温度越高的BYT薄膜,其结晶度越高。并且发现,BYT薄膜的剩余极化值(2Pr)在710℃以下随退火温度增高而增大,在710℃达到最大;在外加400kV/cm电场时2Pr为36.7μC/cm2,然后随退火温度上升又有所下降。 相似文献
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采用脉冲激光沉积方法(PLD)制备了Au/PZT/BIT/p-Si多层结构铁电存储二极管.对铁电存储二极管的P-E电滞回线、I-V特性曲线分别进行了测试与分析,并对其导电行为及基于I-V特性回滞现象的存储机理进行了讨论.实验表明,所制备的多层铁电薄膜具有较高的剩余极化(27μC/cm2)和较低的矫顽场(48kV/cm),BIT铁电层有助于缓解PZT与Si衬底之间的界面反应和互扩散,减少界面态,与Au/PZT/p-Si结构相比,漏电流密度降低近两个数量级,I-V特性曲线回滞窗口明显增大. 相似文献
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准分子激光扫描淀积PZT/YBCO结构铁电薄膜 总被引:2,自引:1,他引:1
利用脉冲准分子激光(工作气体XeCl,波长308nm,脉宽28ns)在外延YBCO/LaAlO3(100)单晶基片上淀积了Pb(Zr0.55Ti0.45)O3铁电薄膜,YBCO薄膜既为生长高取向PZT薄膜提供了晶体匹配条件,同时也为PZT铁电薄膜提供了下电极。讨论了工艺参数对晶相结构和表面形貌的影响。用X射线衍射表征了该多层膜的晶相结构,扫描电镜观察其表面形貌。PZT铁电薄膜的剩余极化为21μC/cm2,矫顽场为65kV/cm。 相似文献
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PZT,PT干凝胶的制备及应用 总被引:2,自引:1,他引:1
采用减压抽滤的方法成功制备了Pb(Zr0.5Ti0.5)O3,PbTiO3干凝胶,并用STA449C差热分析仪表征了干凝胶的性能。干凝胶溶解后得到了性能优良的PZT薄膜和PZT/PT复合膜。采用X射线衍射技术表征了两种薄膜的微观结构及成相特征。薄膜的介电性能及漏电流性能由HP4284ALCR及Keithley6517A来确定。试验结果表明:用减压抽滤得到的干凝胶的方法,可以彻底解决溶胶凝胶中先体存放的问题,得到的铁电薄膜有优良的介电与铁电性能。PZT的相对介电常数与介质损耗分别为424,0.033,PT作为中间层的复合膜的相对介电常数和介质损耗分别为261,0.014;PT薄膜可以调整和改进PZT薄膜的性能,使之达到应用于热释电探测器的要求。 相似文献
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底电极对PYZT铁电薄膜电容器的影响 总被引:1,自引:1,他引:0
PYZT铁电薄膜电容器的制备采用sol-gel方法,将约500nm厚的PYZT薄膜沉积在Pt/Ti、Pt/SiO2及Pt/RuO2底电极上,基片为Si(111)。详细分析研究了PYZT薄膜在不同底电极,不同快速热处理温度下的晶相结构及PYZT铁电薄膜电容器的小信号特性。研究发现,沉积在Pt/RuO2底电极上的PYZT薄膜经800℃快速热处理具有较接近理想外延PYZT薄膜结构,而且εr随着快速热处理温度升高而减小,在800℃快速热处理条件下其εr约为150。 相似文献
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Zhen-Kui Shen Zhi-Hui Chen Zhi-Jun Qiu Bing-rui Lu Jing Wan Shao-Ren Deng An-Quan Jiang Xin-Ping Qu Ran Liu Yifang Chen 《Microelectronic Engineering》2010,87(5-8):869-871
The ferroelectric random access memory (FRAM) which uses ferroelectric thin film as memory material is considered to be a candidate for the next generation memory application. In this work, we apply nano-embossing technology to fabricate Pb(Zr0.3,Ti0.7)O3 (PZT) ferroelectric thin film nanostructures and investigate the influence of the patterning process on the material and ferroelectric properties by using SEM, XRD and Precision Ferroelectric Tester. Embossing process has been optimized for embossing depth and pattern profile. It was found that embossing will result in (1 0 0) preferred orientation of the PZT thin film. The electrical characteristics of patterned and un-patterned PZT films have been also studied for comparison. 相似文献
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Ashok Kumar M. R. Alam A. Mangiaracina M. Shamsuzzoha 《Journal of Electronic Materials》1997,26(11):1331-1334
Ferroelectric lead-zirconate-titanate (PZT) thin films were deposited by the pulsed laser deposition technique on Pt-coated
(100) Si substrates. This study was focused on the investigation of the PZT film growth on (100) Si substrate at varying deposition
parameters and electrical characterization of the films including hysteresis loop and fatigue properties by RT66A Standardized
Ferroelectric Test System. PZT deposited at higher temperature (575°C in 450 mTorr O2 partial pressure) showed the best crystalline structure. The remnant polarization and the retained polarization of the ferroelectric
capacitors were 13 μC/cm2 and 20 μC/cm2, respectively. The crystallographic properties of the films were determined using the x-ray diffractometer method. The cross-sectional
transmission electron microscope results showed very smooth interfaces among different layers of films. 相似文献
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Novel capacitor process using diffusion barrier rounded by Si3N4 spacer for high density FRAM device
Bon Jae Koo Yoon Jong Song Sung Yung Lee Dong Jin Jung Hyun Ho Kim Suk Ho Joo Yong Tak Lee Kinam Kim 《Electron Device Letters, IEEE》2000,21(6):280-282
A novel capacitor process was successfully implemented in 4 Mb FRAM device by developing a barrier layer rounded by Si3N4 spacer (BRS) scheme. Using this process, it is possible to eliminate an undesired barrier etching damage, which is a major role in degrading ferroelectric properties. The novel capacitor process was generated by etching an Ir barrier layer and rounding the barrier by a Si3N4 spacer before preparing Pb(Zr 1-xTix)O3 (PZT) films. It was observed that uniform sol-gel derived PZT films were prepared on the patterned Ir substrate by using Si3N4 spacer, which provides a smooth edge of the patterned cell. The contact resistance between bottom electrode and polysilicon plug after full integration was monitored below 700 Ω per contact with contact size 0.6×0.6 (μm2). Compared to the ferroelectric capacitor damaged by barrier etching, the novel Pb(Zr1-xTix)O3 (PZT) capacitor exhibited a well-saturated Q-V curve. The fully processed novel capacitor having 1.2×1.2 (μm2) effective area displayed remnant polarization of 14 (μC/cm2) at an operating voltage of 3.0 V. The BRS ferroelectric capacitor showed a reliable retention property until 100 h at 125°C. Same state retention (Qss) was stable with time up to 100 h while opposite state retention (Qos) showed a log-linear decay rate at 125°C thermal stress 相似文献
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采用准分子脉冲激光沉积(PLD)工艺,制备了Au/PZT/p-Si结构铁电存储二极管.在氧气氛350℃低温沉积、原位530℃快速退火工艺条件下,获得了多晶纯钙钛矿结构的Pb(Zr0.52Ti0.48)O3(PZT)铁电薄膜.PZT薄膜的铁电性能测试显示较饱和的、不对称的电滞回线,其剩余极化和矫顽场分别为13μC/cm2和48kV/cm.从C-V和I-V特性曲线观察到源于铁电极化的回滞现象,记忆窗口约1.1V,+4V偏压下电流密度为3.9×10-6A/cm2. 相似文献
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用PLD方法在铂金硅衬底制作了高质量的SrB i2Ta0.6Nb1.4O9(SBTN)铁电薄膜样品.研究了SBTN薄膜的电学和光学疲劳特性,分析了其机制.结果显示SBTN铁电薄膜,在电场疲劳下,具有无疲劳特性的优良电学性质;然而,在0.9 V电场下,用200W汞灯疲劳样品,发现光诱导极化疲劳明显,与疲劳前相比,剩余极化下降了51%.这种光诱导剩余极化减小的疲劳,主要机理是光生载流子电畴钉扎. 相似文献