Thickness dependence of the optical constants of oxidized copper thin films based on ellipsometry and transmittance

Thin oxidized copper films in various thickness values are deposited onto quartz glass substrates by electron beam evaporation. The ellipsometry parameters and transmittance in a wavelength range of 300 nm-1000 nm are collected by a spectroscopic ellipsometer and a spectrophotometer respectively. The effective thickness and optical constants, i.e., refractive index n and extinction coefficient k, are accurately determined by using newly developed ellipsometry combined with transmittance iteration method. It is found that the effective thickness determined by this method is close to the physical thickness and has obvious difference from the mass thickness for very thin film due to variable density of film. Furthermore, the thickness dependence of optical constants of thin oxidized Cu films is analyzed.

EFFECT OF FABRICATION ON HIGH CYCLE FATIGUE PROPERTIES OF COPPER THIN FILMS

The influence of fabrication on the tensile and fatigue behavior of copper films manufactured by 3 kinds of fabrication methods was investigated. The tensile and high cycle fatigue tests were performed using the test machine developed by authors. Young＇s moduli （72, 71 and 69 GPa, respectively） are lower than the literature values （108-145 GPa）, while the yield strengths were as high as 358, 350 and 346 MPa, respectively and the ultimate strengths as 462, 456 and 446 MPa, respectively. There is not much difference in the tensile properties of the 3 kinds of films. There is little difference in the fatigue properties of the 3 kinds of films but one of them has shorter fatigue life than others in high cycle region and longer fatigue life than others in low cycle region.

Surface removal of a copper thin film in an ultrathin water environment by a molecular dynamics study

The surface planarity and asperity removal behavior on atomic scale in an ultrathin water environment were studied for a nanoscale process by molecular dynamics simulation.Monolayer atomic removal is achieved under both noncontact and monoatomic layer contact conditions with different water film thicknesses.The newly formed surface is relatively smooth without deformed layers,and no plastic defects are present in the subsurface.The nanoscale processing is governed by the interatomic adhering action during which the water film transmits the loading forces to the Cu surface and thereby results in the migration and removal of the surface atoms.When the scratching depth≥0.5 nm,the abrasive particle squeezes out the water film from the scratching region and scratches the Cu surface directly.This leads to the formation of trenches and ridges,accumulation of chips ahead of the particles,and generation of dislocations within the Cu substrate.This process is mainly governed by the plowing action,leading to the deterioration of the surface quality.This study makes the"0 nm planarity,0 residual defects,and 0 polishing pressure"in a nanoscale process more achievable and is helpful in understanding the nanoscale removal of materials for developing an ultra-precision manufacture technology.

Preparation and operation characteristics of organic semiconductor transistor using thin film Al gate and copper phthalocyanine

The organic static induction transistors (OSITs) are fabricated by the method of evaporating and plating in a vacuum with copper phthalocyanine (CuPc) dye, and has a five layered structure of Au/CuPc/Al/CuPc/Au. The experiment reveals that OSITs have obtained a low driving voltage, high current density and high switch speed such as I_ DS = 1.2×10 -6 A/mm2, and the degree of 1 000 Hz. The OSITs have excellent operation characteristics of typical static induction transistors.

Reactive DC Magnetron Sputtering Deposition of Copper Nitride Thin Film

Copper nitride thin film was deposited on glass substrates by reactive DC （direct current） magnetron sputtering at a 0.5 Pa N2 partial pressure and different substrate temperatures. The as-prepared film, characterized with X-Ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy measurements, showed a composed structure of Cu3N crystallites with anti-ReO3 structure and a slight oxidation of the resulted film.The crystal structure and growth rate of Cu3N films were affected strongly by substrate temperature. The preferred crystalline orientation of Cu3N films were （111） and （200） at RT, 100℃. These peaks decayed at 200℃ and 300℃ only Cu （111） peak was noticed. Growth of Cu3N films at 100℃ is the optimum substrate temperature for producing high-quality （111） Cu3N films. The deposition rate of Cu3N films estimated to be in range of 18-30 nm/min increased while the resistivity and the microhardness of Cu3N films decreased when the temperature of glass substrate increased.

Study of Structural and Morphological Properties of Vacuum Coated Copper (Cu) Metal Thin Film

This study presented a technique to deposit high strength and highly conductive copper thin films on glass substrates at room temperature. In this work, Cu thin films with thicknesses ~500 nm have been deposited on glass substrate by thermal evaporation technique at room temperature. After deposition, these films have been annealed at 200°C for 10 - 40 minutes. The thickness and annealing effect on the structural and morphological properties were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The results showed that by increasing thickness the copper films crystallinity in (111) direction had been increased. Also by varying the annealing time the significant changes were observed in the films crystallinity and surface morphology.

Synthesis and Characterization of Metal Organic Chemical Vapour Deposited Copper Titanium Oxide (Cu-Ti-O) Thin Films from Single Solid Source Precursor

Thin films of copper titanium oxide were deposited by metal organic chemical vapour deposition technique from the synthesized single solid source precursor, copper titanium acetylacatonate Cu [Ti(C5H7O2)3] at the deposition temperature of 420°C. The deposited films were characterized using Rutherford Backscattering Spectroscopy, Scanning Electron Microscopy with Energy Dispersive X-Ray facility attached to it, X-Ray Diffractometry, UV-Visible Spectrometry and van-der Pauw Conductivity measurement. Results show that the thickness of the prepared film is determined as 101.236 nm and the film is amorphous in structure, having average grain size of approximately 1 μm. The optical behaviour showed that the absorption edge of the film was at 918 nm near infrared with corresponding direct energy band gap of 1.35 eV. The electrical characterization of the film gave the values of resistivity, sheet resistance and conductivity of the film as 3.43 × 10-1 Ω-cm, 3.39 × 106 Ω/square and 2.91 (Ω-cm)-1 respectively.

Influence of Thickness on the Photosensing Properties of Chemically Synthesized Copper Sulfide Thin Films

We report here the influence of thickness on the photosensing properties of copper sulfide (CuS) thin films. The CuS films were deposited onto glass substrate by using a simple and cost effective chemical bath deposition method. The changes in film thickness as a function of time were monitored. The films were characterized using X-ray diffraction technique (XRD), field emission scanning electron microscopy (FE-SEM), optical measurement techniques and electrical measurement. X-ray diffraction results indicate that all the CuS thin films have an orthorhombic (covellite) structure with preferential orientation along (113) direction. The intensity of the diffraction peaks increases as thickness of the film increases. Uniform deposition having nanocrystalline granular morphology distributed over the entire glass substrate was observed through FE-SEM studies. The crystalline and surface properties of the CuS thin films improved with increase in the film thickness. Transmittance (except for 210 nm thick CuS film) together with band gap values was found to decrease with increase in thickness. I-V measurements under dark and illumination condition show that the CuS thin films give a good photoresponse.

Effects of Annealing Temperature on the Properties of Copper Films Prepared by Magnetron Sputtering

Copper oxide thin films were prepared by a direct-current magnetron sputtering method followed by a thermal annealing treatment at 100-500 ℃. The obtained films were characterized by X-ray diffraction, UV-vis absorption spectroscopy, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. With the increase of the annealing temperature, it was found that the films transformed sequentially from amorphous to single-phase Cu （100℃）, mixed-phase of Cu and Cu2O （150 ℃）, single-phase Cu2O （200 ℃）, then to mixed-phase of Cu2O and CuO （300 ℃）, and finally to single-phase CuO （400 - 500 ℃）. Further analyses indicated that the Cu/Cu2O thin films and the Cu：O thin films presented no further oxidation even on the surface in air atmosphere. Additionally, the visible-light photocatalytic behavior of the copper oxide thin films on the degradation of methylene blue （MB） was also investigated, indicating that the films with pure Cu2O phase or Cu/Cu2O mixed phases have excellent photocatalytic efficiencies.

Activator-assisted electroless deposition of copper nanostructured films

This paper showed simple and effective synthesis of copper nanoparticles within controlled diameter using direct electroless deposition on glass substrates, following the sensitization and activation steps. Electroless-deposited metals, such as Cu, Co, Ni, and Ag, and their alloys had many advantages in micro- and nanotechnologies. The structural, morphological, and optical properties of copper deposits were characterized using X-ray diffraction （XRD）, atomic force microscopy （AFM）, and UV-Vis spectroscopy. The structural data was further analyzed using the Rietveld refinement program. Structural studies reveal that the deposited copper prefers a （111） orientation. AFM studies suggest the deposited materials form compact, uniform, and nanocrystalline phases with a high tendency to self-organize. The data show that the particle size can be controlled by controlling the activator concentration. The absorption spectra of the as-deposited copper nanoparticles reveal that the plasmonic peak broadens and exhibits a blue shift with decreasing particle size.

Effect of Substrate on CuS/PVA Nanocomposite Thin Films Deposited on Glass and Silicon Substrate

Transition metal chalcogenide nanocomposite thin films deposited by chemical routes are currently attracting wide attention being inexpensive, simple and have utility for large area applications. The role of substrate becomes very important in film deposition as well as in controlling their properties due to strain induced properties modification and lattice mismatch. CuS/PVA nanocomposite thin films were successfully deposited on glass and silicon substrates using sol-gel technique. Thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-visible (UV-VIS) and Raman spectroscopy. Structural data confirm the amorphous nature of as grown films which transform into crystalline films after annealing at 200°C. The degree of crystallinity seems to be better in film deposited on silicon substrate in comparison to those grown over glass substrate with average crystallite sizes ≅?4.00 nm and 7.00 nm for films deposited on glass and silicon substrate respectively. Atomic force microscopy (AFM) images in dynamic as well as contact modes display nanoparticles embedded in polymer network. The films surface roughness parameters quantitatively estimated from AFM micrographs are compared. Raman spectra show a sharp peak at ≅474 cm¯1 assigned to S-S stretching mode of S2 ions in films grown on both substrates and associated as due to presence of hexagonal (covellite) crystal structure. Optical band gaps of thin film on glass and silicon substrate are 2.10 eV and 2.02 eV respectively. The effect of substrate on the measured properties is discussed.

Modification of the Properties of Cu_x S Thin Films by Low Energy Ion Beam Implantation

Cu x S thin films are implanted by low energy N + ion beam. The influences of the energy and dose of N + ion implantation on Cu x S films are investigated. The results show that the ratio of copper to sulfur is increased to some extent, the constituents of the film are turned to rich copper phase from rich sulfurous phase after ion beam irradiation. X-ray diffraction spectrum and optical transmission spectra of sample have confirmed the results.

Determination of Hypoxanthine in the Presence of Copper by Adsorptive Stripping Voltammetry

A stripping method for the determination of hypoxanthine in the presence of copper at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation of hypoxanthine-copper at the thin-film mercury electrode followed by a fast linear scan voltammetric measurement of the surface species. Optimum experimental conditions were found to be the use of 1.0 × 10﹣3 mol·L﹣1 NaOH solution as electrolyte supporting, an accumulation potential of ﹣0.50 V and a linear scan rate of 200 mV·s﹣1. The response of hypoxanthine-copper is linear over the concentration ranges of 10 - 60 ppb. For an accumulation time of 30 minutes, the detection limit was found to be 250 ppt (1.8 × 10﹣9 mol·L﹣1). Adequate conditions for measuring the hypoxanthine in the presence of metal ions, xanthine, uric acid and other nitrogenated bases were also investigated. The utility of the method is demonstrated by the presence of hypoxanthine associated in ATP or ssDNA.

Studying the operation characteristics and structure of vertical channel copper-phthalocyanine organic semiconductor transistor

The creation of Au/CuPc/Al/CuPc/structure is a perpendicular type electricity found in the channel of organic static induction transistor. In the following we analyze transistor operation characteristics and machine structural relation. The results express that the transistor drives the voltage low and has no-saturation current-voltage characteristics. Its operation characteristics are dependant on gate bias voltage and the construction of the aluminum electrode.The vertical channel of organic static induction transistor (OSIT), with structure of Au/CuPc/Al/CuPc/Cu, has been determined. According to the test results, the relation of its operation characteristics and device structure was analyzed. The results show that this transistor has a low driving voltage and unsaturation I-V characteristics. Its operation characteristics are dependant on gate bias voltage and the structure of the aluminum electrode.

不同环境下硫化镉/铜基薄膜异质结退火对太阳电池性能调控

高效铜基薄膜太阳电池通常采用无机n型半导体材料CdS作为缓冲层,因此,缓冲层与吸收层之间的界面质量和能带匹配对载流子的收集利用至关重要.在优化CdS基础工艺的基础上,在含硫气氛下对硫化镉/铜基薄膜异质结进行退火的策略进一步提高CdS薄膜质量,并将其应用到铜基太阳电池,调控铜基薄膜电池p-n异质结能带匹配.研究表明,CdS薄膜在含硫的惰性气氛中退火可以有效提高CdS薄膜的结晶质量并抑制CZTS/CdS异质结界面的非辐射复合,器件的开路电压得到大幅提升,最高可达718 mV.在器件效率方面,基于溅射法的CZTS太阳电池效率从3.47%提升到5.68%,约为不退火处理的2倍.该研究为铜基薄膜太阳电池器件实现高开路电压提供了可靠的工艺窗口.同时,有力地说明了退火气氛选择对于CdS质量以及CZTS/CdS异质结能带匹配的重要性,除了界面互扩散以外,对薄膜材料组分及其结晶性等均实现了调控.

A simple chemical route to synthesize the umangite phase of copper selenide(Cu3Se2) thin film at room temperature

Copper selenide（Cu3Se2/thin films have been synthesized with Se as the precursor in aqueous solution by chemical bath deposition technique at room temperature.We have investigated the influence of the growth time ranging from 30 to 90 min on structural,optical and electrical properties of Cu3Se2 thin films.The as-grown film at 60 min exhibits a tetragonal structure and is（101）oriented.The maximum value of crystal size DD55 nm is attained for Cu3Se2 films grown at 60 min.The Raman spectrum reveals a pronounced peak at 259 cm 1,which is assigned to vibrational（stretching）modes from the covalent Se–Se bonds.The optical band gap energy is 1.91 to2.01 eV with growth time increased from 30 to 90 min.The scanning electron microscopy（SEM）study reveals that the grains are uniform and spread over the entire surface of the substrate of the film at 60 min.The Hall effect study reveals that the film exhibits p-type conductivity.The synthesized film showed good absorbance in the visible region which signifies that synthesized Cu3Se2 films can be suitable as a sensitized material in semiconductor sensitized solar cells.

Cu_2O薄膜的可控制备及对次甲基蓝的光催化降解

采用电化学沉积法在掺锡氧化铟(ITO)导电玻璃上通过加入不同添加剂制备了不同形貌的Cu2O薄膜,利用XPS、XRD、SEM及UV-Vis对Cu2O薄膜的微观结构、表面形貌及光学特性进行了表征和分析,研究了不同形貌的Cu2O薄膜在H2O2-Cu2O薄膜体系中对次甲基蓝的降解。结果表明,所制得Cu2O薄膜为较纯的微米级Cu2O晶体,作为光催化剂,Cu2O薄膜3 h内对次甲基蓝的降解率均可达92.1%以上。无添加剂的Cu2O薄膜在前8次重复利用中降解率均可达92.4%以上,利用11次后仍具有较好的光催化活性,降解率可达82.4%。

基于p-6P异质诱导生长酞菁铜薄膜的NO_2传感器

为实现室温下低浓度NO2气体检测,制作了p-六联苯(p-6P)诱导层的酞菁铜有机薄膜传感器。利用原子力显微镜(AFM)研究了不同沉积速率下p-6P薄膜的生长规律,慢速沉积提供足够的分子扩散时间,利于薄膜横向生长,形成高度低、尺寸大的晶畴。在p-6P薄膜上生长了酞菁铜薄膜,可以清晰看到晶畴上酞菁铜薄膜的有序排列。利用X射线衍射(XRD)仪,阐明了p-6P对酞菁铜薄膜具有很好的诱导效应。通过对比不同沉积速率p-6P薄膜诱导的酞菁铜传感器性能,发现慢速沉积诱导层的酞菁铜器件有高的响应强度和低的回复时间。异质诱导生长的酞菁铜传感器响应强度是直接生长在二氧化硅上的酞菁铜传感器的2倍,回复时间是3.2 min,对浓度为1.0×10^(-5)的NO_2气体灵敏。

热处理对PI基板铜薄膜金属化TiN阻挡层的影响

聚酰亚胺(PI)材料具有介电常数低,分解温度高及化学稳定性好等优点,是很有前途的电子封装材料。Cu具有低的电阻和高的抗电迁移能力,是PI基板金属化的首选材料。采用物理气相沉积(PVD)方法在PI 基板上沉积Cu薄膜,利用TiN陶瓷薄膜阻挡Cu向PI基板内部扩散。研究热处理条件下TiN陶瓷薄膜阻挡层的阻挡效果、Cu膜电阻变化以及Cu膜的结合强度,俄歇谱图分析表明TiN可以有效地阻挡Cu向PI内的扩散。300℃热处理消除了Cu膜内应力,提高了Cu膜的结合强度。

CIS和CIGS薄膜太阳电池的研究

采用蒸发硒化方法制备了P型CIS(铜铟硒 )和CIGS(铜铟镓硒 )薄膜 ,用蒸发法制备N型CdS(硫化镉 ) ,二者组成异质PN结太阳电池。经退火处理 ,CIS和CIGS薄膜太阳电池的效率分别达到 8 83 %和 9 13 %。对制膜过程中衬底的选择 ,背电极的制备 ,CIS各元素蒸发控制和镓的掺入等工艺技术问题进行了深入的讨论 。