感光性溶胶-凝胶法在功能薄膜微细图形与微阵列中制备中的应用

以硅为代表的半导体的微细加工技术已达到了亚微米甚至纳米级的水平,而沿用半导体微细加工技术的功能薄膜的微细加工则远达不到这样的水平,其主要原因之一是由于功能薄膜通常含有多种化学组元,各种元素的抗蚀能力不同,与硅半导体相比,微细图形制备具有更大的难度.本研究结合功能薄膜的特点,研究了感光溶胶-凝胶技术,在薄膜的制备过程中就考虑到薄膜的微细加工.这种方法充分利用了溶胶-凝胶法可精确调控薄膜成分、按照需要对薄膜的结构进行化学裁剪的特点,用化学修饰法赋予薄膜以感光特性,利用薄膜自身的感光特性制备微细图形,简化了薄膜微细图形制备流程,并可以获得具有亚微米级的功能薄膜阵列或二维格子,在光电子或微电子领域有重要应用前景.     

LaNiO3凝胶薄膜微细图形的制备

采用溶胶-凝胶工艺,以Ni(Ac)_2、La(NO_3)_3为前驱原料,以乙醇和乙二醇甲醚为溶剂,以丙烯酸为稳定剂,乙酰丙酮(AcAc)为化学修饰剂制备了感光性LNO溶胶。通过其溶胶的紫外和红外吸收光谱研究了感光性LNO溶胶的紫外感光机理,并运用溶胶-凝胶直接感光法制备出LNO薄膜的微细图形。     

钇稳定氧化锆薄膜的制备及其微细加工

以甲醇为溶剂,硝酸氧锆、硝酸钇为前驱物,采用溶胶-凝胶方法,通过引入化学修饰剂乙酰丙酮(AcAcH),使乙酰丙酮和锆离子形成螯合物,得到了具有紫外光感光性的溶胶及其凝胶薄膜,提出了YSZ薄膜的微细图形加工新方法.UV-Vis.分光光度计的紫外光谱测试结果表明:乙酰丙酮与锆离子形成的螯合物在室温、可见光、大气环境下,可以存在于凝胶薄膜中,并具有较好的热稳定性和光化学稳定性,其紫外光谱的特征吸收峰大约在310nm附近;325nm紫外激光光源照射凝胶薄膜,能破坏、分解凝胶薄膜中的这种螯合物结构,使凝胶薄膜的物理化学性质发生变化,实验发现,经过紫外激光照射的凝胶薄膜在适当的有机溶剂(如甲醇等)中的溶解度和溶解速度显著降低,利用这一特性,采用325nm紫外激光通过掩膜照射凝胶薄膜,并在适当的有机溶剂中溶洗掉未受照射的区域,经过800℃,20min热处理,得到了具有微细图形的YSZ薄膜,XRD测试表明该薄膜相结构为立方相.     

高温超导薄膜微细图形制备工艺的研究进展

高温超导薄膜具有良好的物理性能,其微细图形在微电子器件中有非常广泛的应用.概述了高温超导薄膜微细图形的制备工艺及研究进展,重点介绍了高温超导薄膜微细图形制备方法中的光刻法、改性工艺、耐熔微掩膜制备法和Sol-gel法与化学修饰法相结合的基本原理、工艺特点及最新研究进展.首次把Sol-gel法与化学修饰法相结合制备薄膜的微细图形的工艺用于高温超导薄膜微细图形的制备中.     

溶胶-凝胶法制备YBCO薄膜及其缓冲层

采用溶胶-凝胶法在硅基板上先分别制备钇稳定氧化锆(YSZ)和钛酸锶(STO)两种薄膜缓冲层。再以钇、钡和铜的醋酸盐为起始原料,选用三种络合剂,配制出了均匀、稳定的 YBCO溶胶;采用提拉法,分别在不同过渡层上制备了 YBCO 薄膜。进一步对 YBCO 纳米薄膜的热处理工艺、薄膜形貌和微观组织结构进行了初步研究。     

直接感光法制备钛酸锶钡图形化薄膜及其性能研究

采用改进的化学修饰的溶胶-凝胶工艺, 以聚乙烯吡咯烷酮(PVP)为薄膜开裂抑制剂, 以乙酰丙酮为化学修饰剂, 利用乙酰丙酮可以与金属盐形成的配位螯合物的特性, 制备了具有紫外光感光特性的钛酸锶钡(Ba_0.8Sr_0.2TiO₃)前驱溶胶及其凝胶薄膜; 结合直接感光法, 首先制备图形化凝胶薄膜, 再通过后续热处理, 在Pt/TiO₂/SiO₂/Si衬底上最终得到了具有钙钛矿结构的钛酸锶钡图形化薄膜, 其图形厚度约为793nm, 相对介电常数约为600, 介电损耗约为0.03.     

溶胶-凝胶法制备MgB_2超导纳米线

采用溶胶-凝胶法和在Ar气氛下热分解技术,制得了MgB2超导晶态纳米线。利用XRD对样品进行物相分析,表明有MgB2生成。通过扫描电子显微镜(SEM)对样品进行形貌分析,证实制备出了MgB2纳米线。样品的超导特性通过电阻随温度变化的测量得以证实,其超导临界转变温度Tc为19.4K。此外,对比分析了溶胶-凝胶法粉末和传统固相烧结粉末的异同。     

非晶ZrO2-SiO2系薄膜及微细图形的制备

采用溶胶－凝胶与化学修饰相结合的方法制备了ZrO2-SiO2系薄膜，研究了这种凝胶薄膜的FT－IR光谱特性及随紫外线照射时的变化，发现在1600－1400cm^-1之间有一些与含锆螯合物相关的峰，这些峰值随紫外线照射而减弱，表明这些螯合物发生分解，伴随着螯合物的分解，薄膜的乙醇中的溶解能力也发生变化，利用这特性，紫外光通过掩膜照射凝胶薄膜，用有机溶剂溶洗后，获得凝胶薄膜的微细图形，再进行热处理，消除薄膜中的有机物就可得到非晶质ZrO2-SiO2系薄膜的微细图形。     

用溶胶—凝胶法制备铁电薄膜

介绍了溶胶－凝胶技术制备铁电薄膜的基本原理，工艺过程及工艺特点，综述了溶胶－凝胶法制备铁电薄膜的最新进展。     

溶胶—凝胶法制备MoO3陶瓷薄膜

以钼酸铵为原料，乙二醇为溶剂，用溶胶－凝胶法制备ＭｏＯ３薄膜，通过对干凝胶粉做ＤＴＡ和ＴＧ分析，用ＳＥＭ和ＸＲＤ分析胶膜，热处理后氧化物膜多次重复浸涂热处理薄膜的显微结构和晶相组成，研究了氧化物薄膜的形成过程，重复４次浸涂热处理可得到的约２μｍ厚连续臻密的，主晶相为择优取向的斜方ＭｏＯ３薄膜。     

YBCO Superconducting Film Coated on LaAlO3 Substrate by TFA-MOD Process

Epitaxial YBCO film was coated on (001) LaAlO₃ single-crystal substrate by metalorganic deposition of metal trifluoroacetate precursors. From XRD and EDS analysis, it was observed that the film contains CuO or Cu₂BaO₂ segregation, but transport measurement found the segregation structure does not severely prevent the percolation of supercurrent-carrying material. The YBCO films performance is up to 2.4 MA/cm² with I_c of 137 A/cm-width at 77 K and 0 T, and superconducting transition temperature T_c reaches around 91.3 K with sharp transition temperature T_c of 0.36 K.     

无氟MOD法制备YBCO超导薄膜工艺中物相的演变过程

第二代高温超导带材在电力系统和磁体领域拥有良好的应用前景, 无氟金属有机盐沉积技术(FF-MOD)以其设备成本低、晶体生长速率快、环境友好等特点, 成为研究热点。本研究通过FF-MOD技术, 在铝酸镧单晶和CeO₂/IBAD-MgO/Y₂O₃/Al₂O₃/Hastelloy C276人工基板上制备得到钇钡铜氧(YBCO)薄膜, 并对不同制备温度下的样品进行淬火, 随后对淬火样品进行了X射线衍射、扫描电子显微镜和衰减全反射红外光谱的表征, 系统地研究了高温成相过程中BaCO₃和YBCO的相演变过程。实验结果表明, 在YBCO成相过程中, BaCO₃不会与Y、Cu元素的氧化物反应直接生成YBCO晶体, 并生成的YBCO相晶体先呈随机取向, 然后在热处理的过程中(800℃左右)逐渐转化为具有双轴织构的YBCO晶体。     

Terahertz Radiation from YBCO Thin Film Log-Periodic Antennas

We study terahertz (THz) radiation properties from YBa₂Cu₃O^7– (YBCO) thin film log-periodic antennas. Three sets of wire grid polarizers are employed to characterize the frequency-dependent polarization of the THz beam excited with a femtosecond laser. The polarized radiation has clear resonance at frequencies corresponding to the antenna structures. InSb hot-electron bolometer is used to estimate the radiation power after being calibrated in the THz beam generation and detection system. The radiation power increases quadratically with increasing bias current and reaches over 20 W in the average at an excitation power of 98 m W.     

衬底温度对掺锆酸钡高温超导YBCO薄膜结构和超导电性能的影响

高温超导氧化物YBCO外延薄膜在掺入少量锆酸钡(BaZrO3,BZO)后,其超导性能会得到较大幅度的提高.研究了不同衬底温度对掺BZO的YBCO薄膜的外延特性及超导性能的影响.以固相反应法制备了YBCO及BZO原材料,利用固相烧结工艺制备了BZO含量为2%(质量分数)的YBCO-BZO复合靶材,采用脉冲激光沉积技术(PLD)在LaAlO3(100)基片上外延生长YBCO薄膜.以不同的衬底温度制备了YBCO薄膜,用X射线衍射和高分辨透射电子显微技术对所制备的YBCO薄膜的外延特性进行了分析.最后比较了在不同衬底温度下制备的YBCO薄膜的超导性能,得到了最佳衬底温度.     

Preparation of YBCO Superconducting Thick Films on MgO Substrates by Modified Melt Growth Process

Superconducting thick films (200–300 m) of YBCO have been fabricated successfully on MgO substrates by a new approach. The precursor powders (YBa₂Cu₃O_7– (Y123) + 0.1 mol Y₂BaCuO₅(Y211)) are placed between two MgO (10 mm×10 mm) slices to form sandwich structure. The YBCO thick films have been obtained from the precursors by modified melt growth process. Resistance measurements of YBCO thick films show T _con of 87.3 K and T of 4.5 K. Estimates using hysteresis loops and the Bean model give a value of 2.78×10³ A/cm² (77 K, 0T) for the critical current density. The observations of scanning electron microscopy (SEM) and X-ray diffraction (XRD) patterns show the supercoducting Y123 phase matrix containing discrete Y211 inclusions.     

A Comparative Study of YBCO Thin Film Growth by Inverted Cylindrical Magnetron Sputtering and Inverted Cylindrical Sputtering

A comparative study of Y₁Ba₂Cu₃O_7–x (YBCOrpar; thin film growth by inverted cylindrical magnetron sputtering and non-magnetron inverted cylindrical sputtering was done. At the total pressure of 40 Pa epitaxial YBCO thin films with good superconducting transition properties and smooth surface were prepared by the magnetron source. Inductive measurements gave = 89.5 K and T _C = 0.5 K. The full width at half maximum (FWHM) value of the rocking curve was 0.18°. The average surface smoothness of the film was 250 Å. With the non-magnetron source at the same total pressure, the superconducting transition properties of the YBCO thin films were not good because of intense bombardment by energetic ions. However, by raising the total pressure to 60 Pa, epitaxial YBCO thin films with good superconducting transition properties and smooth surface could be prepared by non-magnetron inverted cylindrical sputtering— = 90.5 K, T _C = 0.5 K. The FWHM value of the rocking curve was 0.23° and the average surface smoothness of the film was 900 Å.     

低氟MOD法制备Zr掺杂YBCO薄膜的研究

在金属有机盐沉积（MOD）法制备YBCO薄膜的工艺中, 采用无F的α甲基丙烯酸铜取代原来的三氟乙酸铜, 可以降低前驱溶液中大约50%的氟含量. 研究表明, 该方法大大缩短了YBCO前驱薄膜受热分解的时间, 仅为原来的1/7. 通过XRD、SEM分析发现, 该方法可以制备成分单一、具有良好立方织构的YBCO薄膜, 且薄膜表面平整致密, 没有裂纹, 临界温度(T_c)达到了90K左右, 77K、自场下的临街电流密度(J_c)达到了2.84MA/cm². 通过在制备的YBCO薄膜中引入6mol% 的 Zr元素掺杂, 有效地提高了YBCO薄膜在外加磁场下的超导性能.     

定向凝固法制备YBCO超导棒材研究

为了使高温超导体YBa2Cu3O7-d(简称YBCO)的晶粒取向排列,提高其临界电流密度,利用定向凝固方法生长YBCO棒材.采用光学显微镜、扫描电子显微镜研究了定向凝固工艺(抽拉速率和添加211粒子)对YBCO显微组织及片层生长的影响.结果表明,改变抽拉速率可以改善片层质量,211粒子是显微组织及片层厚度的重要影响因素;较低的抽拉速率有利于高质量定向结构的生长;均匀分布的细小Y211粒子会使片层厚度变薄,晶界连通性改善,有利于YBCO的生长.     

Nb掺杂YBCO薄膜钉扎机理的研究

通过低氟MOD法制备了Nb掺杂的YBa₂Cu₃O_7-x(YBCO)薄膜, 掺入的Nb以Ba₂YNbO₆(BYNO)相存在, 其尺寸大小在20~30 nm之间, 薄膜中BYNO纳米颗粒以外延和随机两种取向共存, 且以随机取向为主。BYNO纳米颗粒的周围出现堆垛层错, 并且BYNO周围的YBCO出现严重的晶格畸变, 这增加了YBCO薄膜内部的微观应变, 且随机BYNO颗粒含量越高, YBCO薄膜内部的微观应变就越大。微观应变增加了薄膜的磁通钉扎能力, 进而提高了薄膜在高磁场下的超导性能。     

Growth and Characterization of YBCO Thin Films by Sequential Deposition and Annealing

A novel thin film growth procedure, sequential deposition and annealing (SDA), which contains the advantages of both in situ and ex situ procedures, was proposed. Y₁Ba₂Cu₃O_{7 – x} (YBCO) high temperature superconducting thin films were grown and characterized by the SDA procedure. Purely c-axis-oriented YBCO thin films with no foreign phases and other oriented grains were successfully prepared. The superconducting transition properties of SDA-grown YBCO thin films were measured by measurement of inductance and resistance. The inductance measurements gave a T _c ^onset of 85 K and a T _c of 5 K. The resistance measurements gave a T _c ^onset of 90 K and a T _c of 5 K. Atomic force microscopy studies showed that SDA-grown YBCO thin films had micrometer-size grains surrounded by many nanometer-size grains. The nanometer-size grains in SDA-grown YBCO thin films are responsible for degradation of superconducting transition properties.