Epitaxial growth of CeO2/yttria-stabilized ZrO2 double layer films on biaxially textured Ni tape via electrostatic spray assisted vapour deposition

Epitaxial growth of CeO₂ and yttria-stabilized ZrO₂ (YSZ) double layer films has been successfully carried out on biaxially textured nickel substrates at a temperature between 400 and 600 °C using electrostatic spray assisted vapour deposition method. The structure of the double layer was characterized by X-ray diffraction and scanning electron microscopy. The results show that highly oriented CeO₂/YSZ double buffer films were formed epitaxially onto biaxially textured Ni substrates. The orientation relationships between YSZ layer and Ni substrate are 001_YSZ//001_Ni and 110_YSZ//100_Ni, while the orientation relationships between CeO₂ and YSZ are 001_CeO2//001_YSZ and 100_CeO2//100_YSZ.     

Filtered vacuum arc deposition of transparent conducting Al-doped ZnO films

Transparent conducting ZnO:Al and ZnO films of 380-800 nm thickness were deposited on glass substrates by filtered vacuum arc deposition (FVAD), using a cylindrical Zn cathode doped with 5-6 at.% Al or a pure Zn cathode in oxygen background gas with pressure P = 0.4-0.93 Pa. The crystalline structure, composition and electrical and optical properties of the films were studied as functions of P. The films were stored under ambient air conditions and the variation of their resistance as function of storage time was monitored over a period of several months.The Al concentration in the film was found to be 0.006-0.008 at.%, i.e., a few orders of magnitude lower than that in the cathode material. However, this low Al content influenced the film resistivity, ρ, and its stability. The resistivity of as-deposited ZnO:Al films, ρ = (6-8) × 10^− 3 Ω cm, was independent of P and lower by a factor of 2 in comparison to that of the ZnO films deposited by the same FVAD system. The ρ of ZnO films 60 days after deposition increased by a factor of ∼ 7 with respect to as-deposited films. The ZnO:Al films deposited with P = 0.47-0.6 Pa were more stable, their ρ first slowly increased during the storage time (1.1-1.4 times with respect to as-deposited films), and then stabilized after 30-45 days.     

Hemocompatibility of lanthanum oxide films fabricated by dual plasma deposition

Lanthanum oxide films were fabricated using dual plasma deposition. X-ray photoelectron spectroscopy (XPS) showed that La existed in the + 3 oxidation state. X-ray diffraction (XRD) revealed a (101) oriented hexagonal structure. Blood platelet adhesion tests and endothelial cell cultures were used to evaluate the hemocompatibility of the as-deposited films. Scanning electron microscopy (SEM) and optical microscopy were employed to evaluate the surface morphology of the blood platelets and endothelial cells on the films. The results showed that the number of adhered, aggregated and morphologically changed platelets was reduced compared to that observed on low-temperature isotropic carbon (LTIC). Endothelial cells culture tests indicated good adhesion and proliferation of human umbilical vein endothelial (HUVE) cells in vitro. Our study suggests that lanthanum oxide films are potential blood-contacting biomedical materials.     

Growth of epitaxial Cu on MgO(001) by magnetron sputter deposition

100-nm-thick Cu layers were grown on MgO(001) substrates by ultra-high vacuum magnetron sputter deposition at substrate temperatures T_s ranging from 40 to 300 °C. X-ray diffraction ω−2θ scans, ω-rocking curves, and pole figures show that layers grown at T_s = 40 and 100 °C are complete single crystals with a cube-on-cube epitaxial relationship with the substrate: (001)_Cu||(001)_MgO with [100]_Cu||[100]_MgO. In contrast, T_s ≥ 200 °C leads to polycrystalline Cu layers with 001, 203, and 1¯75-oriented grains. The transition from a single- to a polycrystalline microstructure with increasing T_s is attributed to temperature-induced mass transport that allows Cu nuclei to sample a larger orientational space and find lower energy (and/or lower lattice mismatch) configurations. The large Cu- to-MgO lattice mismatch of 14% is relieved by 7 × 7 Cu unit cells occupying 6 × 6 MgO cells. In addition, for T_s ≥ 200 °C, the 001-oriented grains relax by tilting by 4° or 15° about 〈110〉 or 〈100〉 axes, respectively, while the 203 and 1¯75-oriented grains exhibit complex epitaxial relationships with the substrate: (203)_Cu||(001)_MgO with [010]_Cu||[110]_MgO and [302¯]_Cu||[11¯0]_MgO; and (1¯75)_Cu||(001)_MgO with [211¯]_Cu||[100]_MgO and [43¯5]_Cu||[010]_MgO. The surface roughness, as determined by X-ray reflectivity, increases with growth temperature. The smoothest layers are grown at 40 °C and exhibit an rms surface and buried interface roughness of 0.7 and 1.4 nm, respectively.     

Integrated plasma-aided nanofabrication facility: Operation, parameters, and assembly of quantum structures and functional nanomaterials

The development, operation, and applications of two configurations of an integrated plasma-aided nanofabrication facility (IPANF) comprising low-frequency inductively coupled plasma-assisted, low-pressure, multiple-target RF magnetron sputtering plasma source, are reported. The two configurations of the plasma source have different arrangements of the RF inductive coil: a conventional external flat spiral “pancake” coil and an in-house developed internal antenna comprising two orthogonal RF current sheets. The internal antenna configuration generates a “unidirectional” RF current that deeply penetrates into the plasma bulk and results in an excellent uniformity of the plasma over large areas and volumes. The IPANF has been employed for various applications, including low-temperature plasma-enhanced chemical vapor deposition of vertically aligned single-crystalline carbon nanotips, growth of ultra-high aspect ratio semiconductor nanowires, assembly of optoelectronically important Si, SiC, and Al_1-xIn_xN quantum dots, and plasma-based synthesis of bioactive hydroxyapatite for orthopedic implants.     

Material properties and growth control of undoped and Sn-doped In2O3 thin films prepared by using ion beam technologies

Undoped (IO) and Sn-doped In₂O₃ (ITO) films have been deposited on glass and polymer substrates by an advanced ion beam technologies including ion-assisted deposition (IAD), hybrid ion beam, ion beam sputter deposition (IBSD), and ion-assisted reaction (IAR). Physical and chemical properties of the oxide films and adhesion between films and substrates were improved significantly by these technologies. By using the IAD method, non-stoichiometry and microstructure of the films were controlled by changing assisted oxygen ion energy and arrival ratio of assisted oxygen ion to evaporated atoms. Relationships between structural and electrical properties in ITO films on glass substrates were intensively investigated by using the IBSD method with changing ion energy, reactive gas environment, and substrate temperature. Smooth-surface ITO films (R_rms ≤ 1 nm and R_p-v ≤ 10 nm) for organic light-emitting diodes were developed with a combination of deposition conditions with controlling microstructure of a seed layer on glass. IAR surface treatment enormously enhanced the adhesion of oxide films to polymer substrate. The different dependence of IO and ITO films' properties on the experimental parameters, such as ion energy and oxygen gas environment, will be intensively discussed.     

Conformal aluminum oxide coating of high aspect ratio structures using metalorganic chemical vapor deposition

The metalorganic chemical vapor deposition of aluminum oxide has been studied over a wide process parameter range. Electrical properties of as-grown and annealed layers have been investigated using planar aluminum/aluminum oxide/silicon capacitors. The best processing conditions resulted in a leakage current of 10 nA/cm² at an equivalent oxide thickness of 3.6 nm. In addition, the film conformality was evaluated on silicon trench structures with aspect ratios of up to 60. Excellent step coverage of over 90% (thickness at trench bottom to thickness at trench middle) was achieved at temperatures below 400 °C and a pressure of 100 Pa. After annealing the electrical properties of these layers, analyzed on planar test structures, were comparable to the results obtained at higher deposition temperature.     

ICPECVD类金刚石膜沉积过程的发射光谱诊断研究

利用发射光谱(Optical emission spectroscopy,OES)对感应耦合等离子体增强化学气相沉积(Inductivelycoupled plasma enhance chemical vapor d印osition,ICPECVD)类金刚石(Diamondlike carbon,DLC)膜过程中的各种基团进行分析,并对不同条件下薄膜沉积速率以及薄膜显微硬度进行测试.分析结果发现,感应耦合等离子体源激发甲烷等离子体中存在比较突出的碳氢离子成分,从而促进形成高硬度的DLC膜.而且射频功率、沉积气压等沉积参数的变化对DLC薄膜沉积过程的中性基团、离子基团以及原子氢等成分都有着明显影响,从而最终影响薄膜沉积过程及薄膜性质.     

溅射超薄Ag膜中的晶格畸变

用直流溅射法制备了厚度从11．9到189．0nm的超薄Ag膜。X射线衍射（XRD）分析表明：样品中的Ag均为面心立方多晶结构，粒径从6.3到14.5nm。通过晶格常数的计算发现：晶格畸变为收缩，且随着粒径的减小收缩率增加，最大值为1．1％。结合不同方法制备纳米Ag材料的研究结果，讨论了影响晶格畸变的主要因素。