二氧化钛薄膜表面粗糙度研究

为了探究二氧化钛(TiO₂)薄膜表面粗糙度的影响因素, 利用离子束辅助沉积电子束热蒸发技术对不同基底粗糙度以及相同基底粗糙度的K9玻璃完成二氧化钛(TiO₂)光学薄膜的沉积。采用TalySurf CCI非接触式表面轮廓仪分别对镀制前基底表面粗糙度和镀制后薄膜表面粗糙度进行测量。实验表明, TiO₂薄膜表面粗糙度随着基底表面的增大而增大, 但始终小于基底表面粗糙度, 说明TiO₂薄膜具有平滑基地表面粗糙的作用; 随着沉积速率的增大, 薄膜表面粗糙度先降低后趋于平缓; 对于粗糙度为2 nm的基底, 离子束能量大小的改变影响不大, 薄膜表面粗糙度均在1.5 nm左右; 随着膜层厚度的增大, 薄膜表面粗糙度先下降后升高。     

高光洁度玻璃基片的表面散射和体散射测量

 提出了一种利用总积分散射（TIS）测量K9玻璃基片表面散射和体散射的实验方法。首先采用磁控溅射技术在基片表面沉积厚度为几十nm的金属Ag薄膜，然后将基片的表面和体区分开考虑，通过TIS测得了基片上下表面的均方根粗糙度， 进而求得基片的总散射和表面散射，最后计算得到了体散射。分别利用TIS和原子力显微镜（AFM）测量了3个样品上表面所镀Ag膜的均方根粗糙度，两种方法所得的均方根粗糙度的数值相差不明显，差值分别为0.08，0.11和0.09 nm, 表明TIS和AFM的测量结果相一致。利用该方法测得3块K9玻璃基片的总散射分别为6.06×10^-4，5.84×10^-4和6.48×10^-4，表面散射介于1.25×10^-4~1.56×10^-4之间，由此计算得到的体散射分别为3.10×10^-4，3.30×10^-4和3.61×10^-4。     

光学薄膜的分层界面散射模型

提出了一种计算光学介质膜系表面总积分散射(TIS)的理论模型。该模型认为,介质膜系粗糙的膜层界面和表面为微观结构不均匀的微薄过渡区;过渡区可用折射率为不同常量的层数足够多的均匀子层来代替,同时这些均匀子层的折射率变化满足指数函数的分布规律。利用矩阵法对积分散射的表达式进行了推导。对于电子束蒸发方法在K9玻璃上沉积的ZrO2单层膜,分层界面散射模型对积分散射的理论计算值要比非相关表面散射模型的计算值更加符合总积分散射仪的实验测量结果。     

利用总积分散射仪对光学薄膜表面散射特性的研究

利用总积分散射仪对不同条件下制备的金属银膜、Y₂O₃稳定ZrO₂（YSZ）薄膜、TiO₂薄膜和1064 nm与532 nm双波长增透膜的表面均方根（RMS）粗糙度和散射特性的变化规律进行了系统研究,并与样品的制备条件、生长过程、材料组成及光学特性等各方面相结合,对测量结果做出了合理解释,从而使总积分散射测量在其他领域的研究得以扩展和应用. 关键词： 光学薄膜 表面散射 总积分散射仪     

多层膜外退火方法制备MgB2超导薄膜

报道了利用电子束蒸发的Mg/B多层膜作为前驱体,然后退火制备MgB2薄膜的工作.实验中发现,采用翻转膜面的退火处理方式可以有效地避免降温过程中Mg蒸气在薄膜表面形成的颗粒凝结,由此稳定地实现了面积为10 mm×10mm,均匀、平整的超导薄膜的制备,Tc达35 K,转变宽度为0.8 K,在5 μm×5 μm的区域内薄膜的平均粗糙度小于10 nm.为了便于后续器件制作过程中的微加工工艺,研究了膜厚小于1000 (A)时薄膜的成相规律,发现当样品厚度减薄后,Te会有明显降低.通过调整前驱薄膜中的不同分层厚度,仍可实现转变温度达30 K以上、厚度约600 (A)的MgB2薄膜,在20 K时的临界电流密度为2.4×106 A/cm2.     

单层柱状结构薄膜体散射的理论研究

电子束蒸发的单层光学薄膜具有明显的柱状结构,薄膜内部折射率的变化较大,由此引起的体散射现象也较明显。基于一阶电磁微扰理论,建立了单层光学薄膜的体散射理论模型,分析了膜层厚度、入射光偏振态、柱状结构因子、非均质性对体散射的影响。研究了纯柱状结构下,电子束蒸发的单层二氧化铪(Hf O2)薄膜体散射的角分布散射值(ARS)随着膜层厚度的变化规律,结果表明纯柱状结构Hf O2薄膜体散射的ARS量级与表面散射完全非相关模型的ARS值相近,并且在特定的膜厚范围内,体散射的ARS值随着膜厚的增大而增大。对于非均质性薄膜,当非均质性一定时,体散射的ARS值随着膜厚的增大而增大;当膜层厚度一定时,体散射的ARS值随着非均质性绝对值的增大而减小。     

氧化钛薄膜调控金属铜的表面等离子体共振特性研究

提出了一种利用氧化钛薄膜对金属铜薄膜表面等离子体共振特性调制的想法。实验中首先使用电子束蒸发制备一批同等厚度的氧化钛薄膜,再利用磁控溅射方法在氧化钛薄膜上沉积厚度为5～80 nm不等的金属铜薄膜。测试结果表明,氧化钛膜层对不同厚度的金属铜薄膜表面等离子体共振增强具有不同调制效果,金属铜薄膜厚度小于20 nm时,底层的氧化钛薄膜对Cu薄膜表面等离子体共振增强效果显著,且随着金属Cu膜层厚度增加表面等离子体共振峰发生蓝移,而当金属铜膜层的厚度超过20 nm时,共振增强效果因金属Cu薄膜消光能力的上升而开始减弱。     

实际加工表面红外激光散射特性的实验研究

为了研究激光在实际加工表面的散射特性,利用分辨率为10 nW的激光功率计PM100D,波长为1550 nm的激光器和精密转台,自行设计并搭建了半球空间中目标表面散射特性的测量系统. 以典型的刨床加工的若干标准粗糙度比较样块为被测目标,在1550 nm红外激光以不同方位照射下,测量了微观具有V形槽结构的不同粗糙度的样块表面的散射功率分布. 实验结果转换成双向反射分布函数后,对比分析了入射光方位、入射角和表面粗糙度对此类典型表面散射特性的影响,并分析了特殊散射场形成的原因. 结果表明,表面纹理、入射角以及粗糙度均对目标表面的散射特性有规律性影响,这一结果对于具有规律性加工纹理表面的散射特性的研究和建模有一定的参考价值,对激光技术在实际加工表面的应用研究提供了一定的基础. 关键词： 散射特性 双向反射分布函数 红外激光 实际加工表面     

Ag/Fe/Ag 纳米颗粒膜磁特性和微结构

"利用对靶磁控溅射法制备了一系列Ag/Fe/Ag纳米薄膜,沉积态样品Fe层厚度固定为35 nm,Ag层厚度为1、2、3、4、5 nm．随后对沉积态样品进行了退火处理,退火温度分别为200、300、400、500、600 ℃ , 退火30 min． 利用VSM测量了样品的磁特性, 利用SPM观察样品表面形貌和磁畴结构,并且利用XRD分析了样品的晶体结构．研究结果表明,沉积态样品随Ag层厚度的变化,垂直和平行膜面矫顽力均先增加后减小．当Ag层厚度为3 nm时,垂直膜面矫顽力最大约为260 Oe,样品颗粒分布均     

利用多层膜生长技术制备纳米印章模板

在纳米印章技术中，为克服电子束刻蚀制备50nm以下线条的技术难点，利用等离子增强化学 气相沉积技术制备了a-Si/SiN_x多层膜，再利用选择性湿法腐蚀或干法腐蚀在横 截面上制备出浮雕型一维纳米级模板. 多层膜子层之间界面清晰陡峭，可以在纳米量级对子 层厚度进行控制，得到了侧壁在纳米尺度上平滑的模板. 通过控制多层膜子层的生长时间， 制备出线条宽度和槽状宽度均为20nm的等间距模板，品质优于电子束刻蚀技术制备的模板. 关键词： 纳米印章模板 多层膜生长技术     

Frequency dependent smoothing of rough surfaces by laser deposition of ZrO<Subscript>2</Subscript>

The development of the surface roughness of amorphous ZrO₂ layers with different thicknesses, which were laser deposited on nanocrystalline Ag surfaces, was analyzed by atomic force microscopy. With increasing ZrO₂ layer thickness first the surface slightly roughens due to island growth, but above a layer thickness of about 30 nm it continuously smoothens. From the power spectral densities it is clear that the smoothing processes are frequency dependent. First the high-frequency surface features vanish before lower roughness frequencies are decreased. Although the starting roughness is only 1 nm, a ZrO₂ layer thickness of about 4 μm is necessary to smooth the long-wavelength surface features. From the decrease of the roughness with ZrO₂ layer thickness and the observed final spectral densities, the dominant smoothing mechanisms were identified as downhill currents, probably induced by the energetic ions impinging on the substrate surface during deposition. PACS 68.35.Ct; 68.37.Ps     

X-ray photoelectron spectroscopy of nano-multilayered Zr-O/Al-O coatings deposited by cathodic vacuum arc plasma

Nano-multilayered Zr-O/Al-O coatings with alternating Zr-O and Al-O layers having a bi-layer period of 6-7 nm and total coating thickness of 1.0-1.2 μm were deposited using a cathodic vacuum arc plasma process on rotating Si substrates. Plasmas generated from two cathodes, Zr and Al, were deposited simultaneously in a mixture of Ar and O₂ background gases. The Zr-O/Al-O coatings, as well as bulk ZrO₂ and Al₂O₃ reference samples, were studied using X-ray photoelectron spectroscopy (XPS). The XPS spectra were analyzed on the surface and after sputtering with a 4 kV Ar⁺ ion gun. High resolution angle resolved spectra were obtained at three take-off angles: 15°, 45° and 75° relative to the sample surface.It was shown that preferential sputtering of oxygen took place during XPS of bulk reference ZrO₂ samples, producing ZrO and free Zr along with ZrO₂ in the XPS spectra. In contrast, no preferential sputtering was observed with Al₂O₃ reference samples. The Zr-O/Al-O coatings contained a large amount of free metals along with their oxides. Free Zr and Al were observed in the coating spectra both before and after sputtering, and thus cannot be due solely to preferential sputtering.Transmission electron microscopy revealed that the Zr-O/Al-O coatings had a nano-multilayered structure with well distinguished alternating layers. However, both of the alternating layers of the coating contained of a mixture of aluminum and zirconium oxides and free Al and Zr metals. The concentration of Zr and Al changed periodically with distance normal to the coating surface: the Zr maximum coincided with the Al minimum and vice versa. However the concentration of Zr in both alternating layers was significantly larger than that of Al. Despite the large free metal concentration, the Knoop hardness, 21.5 GPa, was relatively high, which might be attributed to super-lattice formation or formation of a metal-oxide nanocomposite within the layers.     

PVP掺杂-ZrO2溶胶-凝胶工艺制备多层激光高反射膜的研究

以丙醇锆(ZrPr)为锆源，二乙醇胺(DEA)为络合剂，原位引入聚乙烯吡咯烷酮(PVP)，在乙醇体系中成功地合成了PVP掺杂-ZrO₂溶胶.采用旋涂法在K9玻璃基片上制备了PVP-ZrO₂单层杂化薄膜.用不同掺杂量的PVP-ZrO₂高折射率膜层与相同的SiO₂低折射率膜层交替沉积四分之一波堆高反射膜.借助小角X射线散射研究胶体微结构，用红外光谱、原子力显微镜、紫外/可见/近红外透射光谱、椭圆偏振仪以及1064nm的强激光辐照实验对薄膜的结构、光学和抗激光损伤性能进行表征.研究发现，体系组成的适当配置可以在溶胶稳定的前提下实现ZrPr的充分水解，赋予薄膜良好的结构、光学和抗激光损伤性能.杂化体系中，DEA与ZPr之间强的配合作用大大降低了ZrO₂颗粒表面羟基的活性，使得PVP大分子只是以微弱的氢键与颗粒的表面羟基作用而均匀分散于ZrO₂颗粒的周围，对颗粒的形成和生长无显著影响.因而在实验研究范围内，随PVP含量的增大，PVP-ZrO₂杂化膜层的折射率和激光损伤阈值均无显著变化.但是，薄膜中均匀分布的PVP柔性链可以有效促进膜层应力松弛，显著削弱不同膜层之间的应力不匹配程度、大大方便多层光学薄膜的制备.当高折射率膜层中PVP的质量分数达到15%—20%时，膜层之间良好的应力匹配使得多层高反射膜的沉积周期数可达到10以上.沉积10个周期的多层反射膜，在中心波长1064nm处透射率约为1.6%—2.1%，接近全反射特征，其激光损伤阈值为16.4—18.2J/cm²(脉冲宽度为1ns). 关键词： 溶胶-凝胶 2')" href="#">PVP-ZrO₂ 高反射膜 激光损伤     

Investigation of interface roughness cross-correlation properties of optical thin films from total scattering losses

The interface roughness and interface roughness cross-correlation properties affect the scattering losses of high-quality optical thin films. In this paper, the theoretical models of light scattering induced by surface and interface roughness of optical thin films are concisely presented. Furthermore, influence of interface roughness cross-correlation properties to light scattering is analyzed by total scattering losses. Moreover, single-layer TiO₂ thin film thickness, substrate roughness of K9 glass and ion beam assisted deposition (IBAD) technique effect on interface roughness cross-correlation properties are studied by experiments, respectively. A 17-layer dielectric quarter-wave high reflection multilayer is analyzed by total scattering losses. The results show that the interface roughness cross-correlation properties depend on TiO₂ thin film thickness, substrate roughness and deposition technique. The interface roughness cross-correlation properties decrease with the increase of film thickness or the decrease of substrates roughness. Furthermore, ion beam assisted deposition technique can increase the interface roughness cross-correlation properties of optical thin films. The measured total scattering losses of 17-layer dielectric quarter-wave high reflection multilayer deposited with IBAD indicate that completely correlated interface model can be observed, when substrate roughness is about 2.84 nm.     

Influences of CO2 laser annealing on mechanical and laser-induced damage properties of ZrO2 thin films

Zirconium dioxide (ZrO₂) thin films were deposited on BK7 glass substrates by the electron beam evaporation method. A continuous wave CO₂ laser was used to anneal the ZrO₂ thin films to investigate whether beneficial changes could be produced. After annealing at different laser scanning speeds by CO₂ laser, weak absorption of the coatings was measured by the surface thermal lensing (STL) technique, and then laser-induced damage threshold (LIDT) was also determined. It was found that the weak absorption decreased first, while the laser scanning speed is below some value, then increased. The LIDT of the ZrO₂ coatings decreased greatly when the laser scanning speeds were below some value. A Nomarski microscope was employed to map the damage morphology, and it was found that the damage behavior was defect-initiated both for annealed and as-deposited samples. The influences of post-deposition CO₂ laser annealing on the structural and mechanical properties of the films have also been investigated by X-ray diffraction and ZYGO interferometer. It was found that the microstructure of the ZrO₂ films did not change. The residual stress in ZrO₂ films showed a tendency from tensile to compressive after CO₂ laser annealing, and the variation quantity of the residual stress increased with decreasing laser scanning speed. The residual stress may be mitigated to some extent at proper treatment parameters.     

Investigation of annealing effects on the laser-induced damage threshold of amorphous Ta2O5 films

Ta₂O₅ films were deposited using the conventional electron beam evaporation method and then annealed at temperatures in the range 373-673 K. Chemical composition, scattering and absorption were examined by X-ray photoelectron spectroscopy (XPS), total integrated scattering (TIS) measurement and the surface thermal lensing (STL) technique, respectively. The laser-induced damage threshold (LIDT) was assessed using the output from an Nd:YAG laser with a pulse length of 12 ns. The results showed that the improvement of the LIDT after annealing was due to the reduced substoichiometric and structural defects present in the film. The LIDT increased slightly below 573 K and then increased significantly with increase in annealing temperature, which could be attributed to different dominant defects. Moreover, the root mean square (RMS) roughness and scattering had little effect on the LIDT, while the absorption and the LIDT were in accord with a general relation.     

Effects of deposition parameters on laser-induced damage threshold of Ta2O5 films

Ta₂O₅ films were deposited on BK7 substrates by e-beam evaporation with different deposition parameters such as substrate temperature (323-623 K), oxygen pressure (0.5-3.0×10⁻² Pa) and deposition rate (0.2-0.5 nm/s). Absorption, scattering and chemical composition were investigated by surface thermal lensing (STL) technique, total integrated scattering (TIS) measurement and X-ray photoelectron spectroscopy (XPS), respectively. The laser-induced damage threshold (LIDT) was assessed using pulsed Nd:YAG 1064 nm laser at a pulse length of 12 ns. The results showed that optical properties, absorption and LIDT were influenced by the deposition parameters and annealing. However, scattering was little correlated with the deposition parameters. On the whole, the LIDT increased with increasing substrate temperature and oxygen pressure, whereas it increased firstly and then decreased upon increasing deposition rate. After annealing at 673 K for 12 h, the LIDT of films improved significantly. The dependence of possible damage mechanism on deposition parameters was discussed.