基于CF_4/Ar高密度感应耦合等离子体的BZN薄膜的刻蚀工艺研究

使用CF4/Ar高密度感应耦合等离子体(ICP)对磁控溅射法制得的铌酸锌铋(BZN)薄膜进行了干法刻蚀工艺研究。分析了BZN薄膜的刻蚀速率随工艺气体流量比、总流量和工作压强的改变而出现极大值的原因,展示了BZN薄膜的刻蚀速率随ICP功率的增大而线性增加的趋势。研究结果表明,使用CF4/Ar感应耦合等离子体对BZN薄膜进行刻蚀的机理为物理辅助的化学反应刻蚀。BZN薄膜的最佳刻蚀工艺参数为CF4/Ar流量比3/2、总流量25sccm、工作压强1.33Pa、ICP功率800W,使用此参数对BZN薄膜进行刻蚀,最大刻蚀速率为26nm/min,刻蚀后薄膜边缘齐整、表面光滑、形状完整。     

太阳电池用绒面结构ZnO-TCO薄膜及光管理研究进展

主要阐述了近年来薄膜太阳电池用绒面结构氧化锌(ZnO)透明导电氧化物(Transparent conductive oxides,TCO)薄膜以及光管理设计方面的研究进展。主要包括溅射湿法刻蚀技术、等离子体刻蚀玻璃衬底技术、等离子体处理修饰ZnO薄膜表面技术、修饰层改善ZnO薄膜表面技术、梯度杂质掺杂技术、复合特征尺寸生长设计以及直接生长绒面结构ZnO薄膜技术和宽光谱ZnO薄膜生长设计等。此外,对薄膜太阳电池中的先进光管理(Light management)结构设计及新材料应用进行了探讨和展望。     

绒面AZO干法制备及性能研究

利用射频溅射方法,制得AZO透明导电膜,并用离子束刻蚀制备绒面,得到绒面AZO透明导电膜。比较刻蚀前后光电性能及表面形貌,发现透过率稍有下降,在可见光波段透过率在80%以上;电阻率略有上升,但仍保持在10-3?·cm数量级,最低为2.91×10-3?·cm;刻蚀后薄膜表面形貌变化较大,大多数薄膜表面呈现"坑状"结构,横向尺寸在0.5?1.0μm,开口角在120°左右,表面粗糙度从7.29nm上升到36.64nm。薄膜具有较好的表面微结构,在作太阳能电池前电极方面有较好的应用前景。     

ICP—CVD制备氟化非晶碳（a—C：F）薄膜的研究

本文使用CH2F2为源气体,利用电感耦合等离子体增强化学气相沉积(ICP-CVD)法在不同放电模式(连续或脉冲)、沉积气压、射频功率和位置下制备了a-C∶F薄膜.用原子力显微镜(AFM)观察了薄膜的表面形貌,通过FTIR、XPS对其结构进行了表征.研究结果表明:放电模式、放电气压、射频功率、基底位置均对薄膜的表面粗糙度(RMS)和组成具有重要的影响.在脉冲波模式下,增加放电气压,薄膜RMS值的变化呈现出先降低后升高的变化趋势;基底距离线圈的距离越远,所沉积薄膜的RMS值越小.而在连续波模式下,距离线圈较远的B、C位置薄膜的RMS值却相对较高.增加放电功率导致沉积薄膜的RMS值较小.本文也对CH2F2等离子体进行了发射光谱(OES)诊断研究.结果表明,对比脉冲波模式,连续波放电时等离子体中含碳物种明显减少.结合表征结果和OES结果对薄膜的生长机理进行了探讨.     

醋酸对绒面AZO薄膜表面织构均匀性的影响研究

以0.5%的稀盐酸中加入一定量醋酸后的溶液为腐蚀液,对利用直流磁控溅射方法制备的平面掺铝氧化锌(AZO)薄膜进行表面织构,并对加入醋酸后的AZO薄膜表面织构均匀性和反应机理进行研究。结果表明:在0.5%稀盐酸中所加醋酸量与盐酸体积比为0.5:1时,对平面AZO薄膜腐蚀45 s能获得更均匀陨石坑状绒面结构,且有较高绒度;腐蚀液中较水分子大得多的醋酸分子的空间位阻作用在一定程度上能减缓腐蚀速率,使得比加醋酸前获得的AZO薄膜绒面更均匀。     

新型相变材料Ti0.5Sb2Te3刻蚀工艺及其机理研究

采用CF4和Ar混合气体研究了新型相变材料Ti0.5Sb2Te3(TST)的刻蚀特性,重点优化和研究了刻蚀气体总流速、CF4/Ar的比例、压力和功率等工艺参数对刻蚀形貌的影响。结果表明,当气体总流量为50 sccm、CF4浓度为26%﹑刻蚀功率为400 W和刻蚀压力为13.3 Pa时,刻蚀速度达到126 nm/min,TST薄膜刻蚀图形侧壁平整而且垂直度好(接近90°)﹑刻蚀表面平整(RMS为0.82 nm)以及刻蚀的片内均匀性等都非常好。     

RF—PECVD聚合类聚乙烯氧（PEO—like）薄膜及其对血小板吸附性研究

本文采用平板式电容耦合射频(RF,13.56MHz)等离子体源,以乙二醇二甲基醚(Ethylene Glycol DiMethyl Ether)为聚合单体,氩气为辅助气体,在连续与脉冲射频等离子体两种放电模式下合成类聚乙烯氧(PEO-like)功能聚合薄膜.实验研究了等离子体放电参数:等离子体放电功率、工作气压、放电模式(连续或脉冲)和聚合时间等对聚合物表面结构、功能团含量、表面成分性能以及和血小板吸附等影响.利用接触角测定仪(WCA)、傅里叶变换红外光谱(FTIR)、原子力显微镜(AFM)等手段对聚合薄膜的结构、成分和形貌进行细致的分析.同时本文还进行体外细胞培养法,研究了类PEO功能薄膜对富血血小板的吸附,通过倒置显微镜观察细胞黏附的数量和形态变化.得到的结论为:采用RF-PECVD可以在较小功率的连续等离子体放电模式,或较长脉冲间隔的脉冲放电模式下得到结构稳定的PEO生物功能薄膜,所制备的PEO生物功能薄膜具有良好的抗血小板吸附性能.     

高气压脉冲DBD等离子体合成胺基功能薄膜及其性能研究

采用高气压脉冲DBD等离子体,以丙烯胺(allylamine)为聚合单体,氩气为辅助气体,合成胺基薄膜.利用接触角测定仪(WCA),傅立叶变换红外光谱(FTIR),原子力显微镜(AFM)对功能薄膜的结构、成分以及形貌进行测试表征.讨论了不同等离子体放电参数,如:气压、占空比、时间和功率对放电沉积薄膜的影响.结论是:高气压脉冲DBD等离子体放电能够有效地聚合含胺基的薄膜,气压、占空比、时间和功率对沉积薄膜有较大的影响.     

微波ECR等离子体刻蚀AAO模板中HfO_2薄膜的研究

采用微波电子回旋共振(ECR)等离子体装置,对用原子层沉积(ALD)方法在阳极氧化铝模板(AAO)上制备的HfO_2薄膜进行了纳米图案化研究。用CF_4、Ar和O_2等离子体,对HfO_2薄膜进行了反应离子束刻蚀,以移除HfO_2。采用高分辨率扫描电子显微镜(SEM)、原子力显微镜(AFM)和能量色散X射线光谱显微(EDX)分析,对样品刻蚀前后的形貌、结构和化学成分进行了表征。实验表明,HfO_2的刻蚀具有定向性,利于高深宽比微机械结构的加工。在其他参数固定的情况下,深宽比高达10∶1的结构中HfO_2的刻蚀速率是微波功率、负脉冲偏压、CF_4/Ar/O_2混合比(Ar含量在0～100%)和工作气压的函数。在0.3 Pa气压、600 W微波功率、100 V偏置电压下,HfO_2拥有0.36 nm/min的可控刻蚀速率,利于HfO_2的精准图案化。刻蚀形貌表明,在CF_4/Ar/O_2等离子体刻蚀之后,刻蚀面非常光滑,具有0.17 nm的均方根线粗糙度。     

掺铝氧化锌透明导电薄膜的表面织构研究

利用中频直流磁控反应溅射法在玻璃衬底上首先制备了掺铝氧化锌(AZO)透明导电薄膜,然后利用5%的氯化铵(NH4Cl)溶液对制备的AZO薄膜进行表面织构。利用扫描电子显微镜(SEM)、四探针法和分光光度计分别测量并研究了织构前后薄膜的表面形貌、电学和光学特性。研究结果表明NH4Cl水溶液容易控制AZO的表面织构过程,并且可以获得较好的绒面。表面织构后,薄膜在可见光波段的平均反射率从12%降低到7.86%,而电阻率略有增大,该结果和表面织构结果一致。     

Varistor properties of ZnO-Pr6O11-CoO-Cr2O3-Y2O3-In2O3 ceramics

The varistor properties of the ZnO-Pr₆O₁₁-CoO-Cr₂O₃-Y₂O₃-In₂O₃ ceramics were investigated for different concentrations of In₂O₃. The increase of In₂O₃ concentration slightly increased the sintered density (5.60-5.63 g/cm³) and slightly decreased the average grain size (3.4-2.9 μm). The breakdown field increased from 6023 to 14822 V/cm with increasing concentration of In₂O₃. The nonlinear coefficient increased from 17.6 to 44.6 for up to 0.005 mol%, whereas the further doping caused it to decrease to 36.8. In₂O₃ acted as an acceptor due to the donor concentration, which decreases in the range of 1.02 × 10¹⁷ to 0.24 × 10¹⁷/cm³ with increasing concentration of In₂O₃.     

Nanocrystallization of SrBi2Nb2O9 from glasses in the system Li2B4O7---SrO---Bi2O3---Nb2O5

Transparent glasses in the system (100−x)Li₂B₄O₇–x(SrO---Bi₂O₃---Nb₂O₅) (10≤x≤60) (in molar ratio) were fabricated by a conventional melt-quenching technique. Amorphous and glassy characteristics of the as-quenched samples were established via X-ray powder diffraction (XRD) and differential thermal analyses (DTA) respectively. Glass–ceramics embedded with strontium bismuth niobate, SrBi₂Nb₂O₉ (SBN) nanocrystals were produced by heat-treating the as-quenched glasses at temperatures higher than 500 °C. Perovskite SBN phase formation through an intermediate fluorite phase in the glass matrix was confirmed by XRD and transmission electron microscopy (TEM). Infrared and Raman spectroscopic studies corroborate the observation of fluorite phase formation. The dielectric constant (_r) and the loss factor (D) for the lithium borate, Li₂B₄O₇ (LBO) glass comprising randomly oriented SBN nanocrystals were determined and compared with those predicted based on the various dielectric mixture rule formalism. The dielectric constant was found to increase with increasing SBN content in LBO glass matrix.     

Characterization of YBa2Cu3O7/PrBa2Cu3O7 superlattices

We investigated the structural and superconducting properties ofc-axis oriented (YBa₂Cu₃O₇) _nY /(PrBa₂Cu₃O₇) _npr superlattices with thicknesses of the individual layers down to one unit cell (10nY1; 18>nPr 1). By transmission electron microscopy and X-ray diffraction we find an excellent structural quality of the samples, though the quantitative analysis shows the existence of defects. In superlattices with decoupled YBa₂Cu₃O₇ layers of two unit cell thickness we find a highT _c value of 75 K. We probed the flux line structure in the superlattices by measurements of the critical current density in magnetic fields. The experiments show that the flux-line dynamics is dominated by the movement of pancake vortices.     

Syntheses of hollandite type Rb2Cr8O16, K2Cr2V6O16 and K2V8O16

Hollandite-type compounds, Rb₂Cr₈O₁₆, K₂Cr₂V₆O₁₆ and K₂V₈O₁₆, were synthesized under high P-T conditions up to 1200°C and 7GPa. The structural refinement using a single crystal of Rb₂Cr₈O₁₆ confirms that the structure is similar to that of K₂Cr₈O₁₆. Magnetic measurements indicate that Rb₂Cr₈O₁₆ is ferromagnetic below 295K, K₂Cr₂V₆O₁₆ paramagnetic down to 77K and K₂V₈O₁₆ has susceptibility anomaly at 175K. These compounds are all semiconductive and show discontinuities in temperature-resistivity curves at points corresponding to magnetic anomalies.     

Magnetic coupling in La0.67Ca0.33MnO3/La0.67Sr0.33CoO3/La0.67Ca0.33MnO3 sandwiches

La_0.67Ca_0.33MnO₃ (LCMO)/La_0.67Sr_0.33CoO₃ (LSCO)/LCMO trilayer films are fabricated on single-crystal substrates NdGaO₃ (110) and the interlayer coupling are investigated. Compared with LCMO single layer, sandwiches showed the enhanced metal-insulator transition temperature of LCMO layers. The magnetoresistance is dependent on spacer thickness and the peak value dramatically decreases when LSCO layer is thick enough because of shorting by the LSCO layer. The magnetic coercivity H_C shows a nonmonotonic behavior with changing spacer layer thickness and the waist-like hysteresis indicates that there is an indirect exchange coupling between the top and bottom LCMO layers across the spacer layer.     

The effect of Bi1.5Zn0.5Nb0.5Ti1.5O7 cover layer on the dielectric and tunable properties of Ba0.6Sr0.4TiO3/Bi1.5Zn0.5Nb0.5Ti1.5O7 bilayered thin films

Bi_1.5Zn_0.5Nb_0.5Ti_1.5O₇ (BZNT) thin films with different thicknesses as cover layers were deposited on the Ba_0.6Sr_0.4TiO₃ (BST) thin films on the Pt/Ti/SiO₂/Si substrates by radio frequency magnetron sputtering method. The microstructure, surface morphology, dielectric and tunable properties of BST/BZNT heterogeneous bilayered films were investigated as a function of the thickness of BZNT films and the effect of BZNT films on the asymmetric electrical properties of BST/BZNT bilayered films was discussed. It was found that BZNT cover layer significantly improved the leakage current and the dielectric loss, and the dielectric constant and tunability of BST/BZNT bilayered thin films simultaneously decreased with the increasing thickness of BZNT films. The BST/BZNT bilayered thin film with a 50 nm BZNT cover layer gave the largest figure of merit (FOM) of 33.48 with the upper tunability of 55.38%. The asymmetric electrical behavior of BST/BZNT bilayered films is probably related to an internal electric field caused by built-in voltages at Pt/BST and BZNT/Au interfaces.     

MoO3-V2O5-P2O5-Fe2O3玻璃的制备及性能研究

制备了MoO3-V2O5-P2O5-Fe2O3系磷酸盐玻璃,研究了玻璃形成能力、热膨胀系数和抗潮解等性能.结果表明,MoO3-V2O5-P2O5-Fe2O3系统具有较宽的玻璃形成区和较强的玻璃形成能力,当MoO3/V2O5≈1.5时,玻璃形成能力最强.MoO3-V2O5-P2O5-Fe2O3玻璃的热膨胀系数约为60～110×10-7/℃,并且随着Fe2O3含量的增加而逐渐增大.加入适量的Fe2O3能够显著改善MoO3-V2O5-P2O5玻璃的抗潮解性能,在90℃的去离子水中的溶解速率达到8.0×10-9g·cm-2·min-1.     

Structural study of Sr0.3Ba0.7Nb2O6 and La0.030Sr0.255Ba0.700Nb2O6 ceramic systems

Sr_0.3Ba_0.7Nb₂O₆ (SBN) and La_0.030Sr_0.255Ba_0.700Nb₂O₆ (LSBN) ceramic compounds have been prepared using the traditional ceramic method at two different calcination temperatures (900 and 1000 °C) and later sintered both at 1400 °C. A study of the effects of the calcination temperatures and La substitution on the morphological, compositional, and structural properties of SBN and LSBN is presented using scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. From Rietveld refinement processes, the XRD patterns were interpreted to evaluate such effects in the structural parameters and the site occupation factors of the heavy metals and oxygen atoms. The effect of the incorporation of La resulted in a 0.25% cell contraction and turned out to be higher than the 0.08% dilation effect produced by the increase of calcination temperature. The La ion with similar effective ionic radius and higher electronegativity is incorporated into the structure occupying the A₁ site just like the Sr ions in the SBN compound. Differences in the site occupation factors between the SBN and LSBN samples lead to substantial changes in the physical properties such as temperature of relative dielectric constant maximum, relative dielectric constant, and dielectric loss, correlated with the distortion and the relative orientation of the oxygen octahedra.     

Microstructures of YBa2Cu3O7/La0.7Ca0.3MnO3 and La0.7Ca0.3MnO3/YBa2Cu3O7 bi-layers grown on (001)LaAlO3

Epitaxial YBa₂Cu₃O₇/La_0.7Ca_0.3MnO₃ (YBCO/LCMO) bi-layers and La_0.7Ca_0.3MnO₃/YBa₂Cu₃O₇ (LCMO/YBCO) bi-layers were grown on (001)LaAlO₃ by pulsed laser deposition, and their microstructures were compared by transmission electron microscopy investigation. In the YBCO(100 nm)/LCMO(150 nm) bi-layers, the LCMO layer consists of columnar grains of ~ 17 nm in diameter and contains mixed orientation domains of [100]_c, [010]_c and [001]_c. The YBCO layer is totally c-axis oriented and the YBCO lattices are tilted − 2.5° to + 2.5° as they grew on the rough surfaces of LCMO columnar grains. For the LCMO(140 nm)/YBCO(140 nm) bi-layers, the LCMO/YBCO interface is sharp and flat. The initial 12-nm thickness of the YBCO layer is composed of c-axis oriented domains, and the upper part of YBCO layer is [100] oriented. The LCMO layer was predominantly [001]_c oriented while [100]_c-oriented domains were occasionally observed.     

MgO-Al2O3-SiO2-TiO2-Y2O3玻璃的弹性模量

根据硬盘基板用材料的要求，制备了MgO-Al2O3-SiO2-TiO2-Y2O3高弹性模量玻璃（120GPa)，玻璃的弹性模量随组成的变化服从Makishima-Mackenzie理论，MgO,Al2O3,TiO2,Y2O3等具有较高单位体积离解能的氧化物有利于提高玻璃的弹性模量，但玻璃弹性模量的理论计算值低于测试值，这是因为Makishima-Mackenzie理论没有考虑玻璃内阳离子的具体配位，对MgO,Y2O3堆积密度因子的堆导存在误差，因此利用Makishima-Mackenzie理论发展高弹性模量玻璃时应对MgO,Y2O3等氧化物的计算进行修正。