低能Ar+离子束辅助沉积择优取向Pt(111)膜

采用低能Ar+离子束辅助沉积方法,在Mo/Si(100)基底上沉积Pt膜,离子/原子到达比分别为0.1、0.2、0.3.若Ar+离子的入射角为0°,XRD谱分析表明,沉积的Pt膜均呈(111)和(200)混合晶向;当Ar+离子的入射角为45°,沉积的Pt膜均呈很强的(111)择优取向.因此若合理控制Ar+离子束的入射角,可在Mo/Si(100)衬底上制备出具有显著择优取向的Pt(111)薄膜.本文采用Monte Carlo方法模拟低能Ar+离子注入 Pt单晶所引起的原子级联碰撞过程,得出Ar+离子入射单晶铂(200)晶面时,Ar+离子的溅射率与入射角的关系,对Pt膜择优取向的机理作了初步的探讨和分析.     

Substrate bias voltage influenced structural, electrical and optical properties of dc magnetron sputtered Ta2O5 films

Tantalum oxide (Ta₂O₅) films were formed on silicon (111) and quartz substrates by dc reactive magnetron sputtering of tantalum target in the presence of oxygen and argon gases mixture. The influence of substrate bias voltage on the chemical binding configuration, structural, electrical and optical properties was investigated. The unbiased films were amorphous in nature. As the substrate bias voltage increased to −50 V the films were transformed into polycrystalline. Further increase of substrate bias voltage to −200 V the crystallinity of the films increased. Electrical characteristics of Al/Ta₂O₅/Si structured films deposited at different substrate bias voltages in the range from 0 to −200 V were studied. The substrate bias voltage reduced the leakage current density and increased the dielectric constant. The optical transmittance of the films increased with the increase of substrate bias voltage. The unbiased films showed an optical band gap of 4.44 eV and the refractive index of 1.89. When the substrate bias voltage increased to −200 V the optical band gap and refractive index increased to 4.50 eV and 2.14, respectively due to the improvement in the crystallinity and packing density of the films. The crystallization due to the applied voltage was attributed to the interaction of the positive ions in plasma with the growing film.     

Nanoindentation and atomic force microscopy measurements on reactively sputtered TiN coatings

Titanium nitride (TiN) coatings were deposited by d.c. reactive magnetron sputtering process. The films were deposited on silicon (111) substrates at various process conditions, e.g. substrate bias voltage (V_B) and nitrogen partial pressure. Mechanical properties of the coatings were investigated by a nanoindentation technique. Force vs displacement curves generated during loading and unloading of a Berkovich diamond indenter were used to determine the hardness (H) and Young’s modulus (Y) of the films. Detailed investigations on the role of substrate bias and nitrogen partial pressure on the mechanical properties of the coatings are presented in this paper. Considerable improvement in the hardness was observed when negative bias voltage was increased from 100–250 V. Films deposited at |V _B| = 250 V exhibited hardness as high as 3300 kg/mm². This increase in hardness has been attributed to ion bombardment during the deposition. The ion bombardment considerably affects the microstructure of the coatings. Atomic force microscopy (AFM) of the coatings revealed fine-grained morphology for the films prepared at higher substrate bias voltage. The hardness of the coatings was found to increase with a decrease in nitrogen partial pressure.     

等离子体辅助反应式脉冲激光熔蚀制备AlN薄膜的低温生长

使用等离子体辅助反应式脉冲激光溅射沉积薄膜的方法在Ｓｉ（１１１）和Ｓｉ（１００）基片上已经成功地低温制备出ＡｌＮ多晶膜。实验表明,当脉冲能量密度ＤＥ＝１．０Ｊ·ｃｍ－２,脉冲频率ｆ＝５Ｈｚ,氮气气压ＰＮ２＝１．３３×１０４Ｐａ,基底温度ｔｓｕｂ＝２００℃,放电电压Ｖ＝６５０Ｖ,基靶距离ｄＳ－Ｔ＝４ｃｍ时薄膜的生长速度等于６ｎｍ／ｍｉｎ。ＡｌＮ薄膜的折射率为２．０５,和基底的取向关系分别为：ＡｌＮ（１１０）∥Ｓｉ（１１１）和ＡｌＮ（１００）∥Ｓｉ（１００）。     

Structural and morphological investigations on DC-magnetron-sputtered nickel films deposited on Si (100)

Pure nickel thin films were deposited on Si (100) substrates under different conditions of sputtering using direct current magnetron sputtering from a nickel metal target. The different deposition parameters employed for this study are target power, argon gas pressure, substrate temperature and substrate-bias voltage. The films exhibited high density of void boundaries with reduction in <111> texture deposited under high argon gas pressures. At argon gas pressure of 5 mTorr and target power of 300 W, Ni deposition rate was ~40 nm/min. In addition, coalescence of grains accompanied with increase in the film texture was observed at high DC power. Ni films undergo morphological transition from continuous, dense void boundaries to microstructure free from voids as the substrate-bias voltage was increased from −10 to −90 V. Furthermore, as the substrate temperature was increased, the films revealed strong <111> fiber texture accompanied with near-equiaxed grain structure. Ni films deposited at 770 K showed the layer-by-layer film formation which lead to dense, continuous microstructure with increase in the grain size.     

Room-temperature growth of AlN/TiN epitaxial multi-layer by laser molecular beam epitaxy

We have fabricated epitaxial AlN thin films at room temperature on sapphire (0001) substrates with a TiN (111) epitaxial buffer layer by pulsed laser deposition in ultra-high vacuum (laser molecular beam epitaxy method). The TiN buffer layers were also fabricated at room temperature. Four-circle X-ray diffraction analysis and reflection high-energy electron diffraction results indicate the heteroepitaxial structure of AlN (0001)/TiN (111)/sapphire (0001) with the epitaxial relationship of AlN [10-10]||TiN [11-2]||sapphire [11-20]. The surface of the room-temperature grown AlN film was found to be atomically flat, reflecting the nano-stepped surface of ultrasmooth sapphire substrates. Then, we could achieve the room-temperature epitaxial growth of [AlN/TiN] multi-layer. The temperature dependence of resistivity of the AlN/TiN multi-layer film was also measured.     

Nanoporous YSZ film in electrolyte membrane of Micro-Solid Oxide Fuel Cell

Yttria stabilized zirconia (YSZ) with 8 mol% Y was deposited by reactive magnetron sputtering onto oxidized (100) silicon substrates. It was possible to switch film texture from (111) to (200) by applying a strong RF substrate bias. Transmission electron microscopy showed that the film deposited under bias is porous and exhibits nanoscaled grains, whereas the film deposited without bias is dense and columnar. The ionic conductivity as a function of temperature revealed an activation energy of 1.04 eV. The mechanical stress could be tuned to low values by thermal post-annealing. Using the dense (111) film as electrolyte layer, and the porous (200) film as an interlayer to a porous Pt anode, an open circuit voltage of 0.85 V was obtained in a micro machined fuel cell structure.     

Optical and mechanical properties of diamond like carbon films deposited by microwave ECR plasma CVD

Diamond like carbon (DLC) films were deposited on Si (111) substrates by microwave electron cyclotron resonance (ECR) plasma chemical vapour deposition (CVD) process using plasma of argon and methane gases. During deposition, a d.c. self-bias was applied to the substrates by application of 13·56 MHz rf power. DLC films deposited at three different bias voltages (−60 V, −100 V and −150 V) were characterized by FTIR, Raman spectroscopy and spectroscopic ellipsometry to study the variation in the bonding and optical properties of the deposited coatings with process parameters. The mechanical properties such as hardness and elastic modulus were measured by load depth sensing indentation technique. The DLC film deposited at −100 V bias exhibit high hardness (∼ 19 GPa), high elastic modulus (∼ 160 GPa) and high refractive index (∼ 2·16–2·26) as compared to films deposited at −60 V and −150 V substrate bias. This study clearly shows the significance of substrate bias in controlling the optical and mechanical properties of DLC films.     

X-ray determination of strain and texture in sputtered molybdenum and titanium films on silicon

Molybdenum and titanium films prepared with a rotating r.f. diode system were examined by X-ray diffraction for strain and texture. Both films were deposited onto (111)-oriented silicon crystal substrates. Molybdenum films 1.13 μm thick sputtered with a target voltage of -2.7 kV, a zero substrate bias and an average temperature of 180°C were in compression on cooling to room temperature. Pole density plots for the (200), (211), (220), (222), (301) and (321) planes gave relatively sharp peaks. The (220) plane showed a strong peak parallel to the (111) plane on silicon. In contrast, a 1.25 μm titanium film was found to be in tension after sputtering at -2.7 kV, a substrate bias of -50 V and an average temperature of 180°C. Relatively broad pole density plots were found for the (002) and (110) planes. The (100) and (110) planes gave peaks parallel to (111) Si. Intrinsic strains from embedded argon were determined from χ scan X-ray data.     

直流负偏压对类金刚石薄膜结构和性能的影响

利用直流-射频-等离子体增强化学气相沉积技术在单晶硅表面制备了类金刚石薄膜，采用原子力显微镜、Raman光谱、X射线光电子能谱、红外光谱、表面轮廓仪和纳米压痕仪考察了直流负偏压对类金刚石薄膜表面形貌、微观结构、沉积速率和硬度等性能的影响。结果表明：无直流负偏压条件下，薄膜呈现有机类聚合结构，具有较低的SP3含量和硬度；叠加上直流负偏压后，薄膜具有典型的类金刚石结构特征，SP3含量和硬度得到了显著的提高；但随着直流负偏压的升高，薄膜的沉积速率和H含量逐渐降低，而SP3含量和硬度在直流负偏压为200V时出现最大值，此后逐渐降低。     

Microcrystalline silicon films fabricated by bias-assisted hot-wire chemical vapor deposition

Microcrystalline silicon films (μc-Si:H) were deposited on stainless steel substrates by bias-assisted hot-wire chemical vapor deposition. The effect of substrate bias and substrate temperature on the crystallinity of μc-Si:H films was studied by Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that both the Raman peak position and the crystalline fraction of the μc-Si:H films deposited at 200 °C were obviously improved by introducing ?800 V substrate bias. The films deposited at 200 °C with ?800 V substrate bias show strongly sharpened Si (111) peak together with Si (220) and Si (311) peaks, which was different from a weak Si (111) peak for those deposited without substrate bias. By increasing the substrate temperature from 200 to 300 °C, while keeping the substrate bias at ?800 V, the crystallinity of the silicon films was further improved, and μc-Si:H films with crystalline fraction of 74 % was obtained.     

Effect of bias voltage on growth property of Cr-DLC film prepared by linear ion beam deposition technique

Cr-containing diamond-like carbon films were deposited on silicon wafers by a combined linear ion beam and DC magnetron sputtering. The influence of the bias voltage on the growth rate, atomic bond structure, surface topography and mechanical properties of the films were investigated by SEM, XPS, Raman spectroscopy, AFM, and nano-indentation. It was shown that the chromium concentration of the films increased with negative bias voltage and that a carbide phase was detected in the as-deposited films. The surface topography of the films evolved from a rough surface with larger hillocks reducing to form a smoother flat surface as the bias voltage increased from 0 to −200 V. The highest hardness and elastic modulus were obtained at a bias voltage of about −50 V, while the maximum sp³ bonding fraction was acquired at −100 V. It was suggested that the mechanical properties of the films not only depended on the sp³ bonding fraction in the films but also correlated with the influence of Cr doping and ion bombardment.     

Morphology and texture evolution of nanostructured CaF2 films on amorphous substrates under oblique incidence flux

The morphology and biaxial texture of vacuum evaporated CaF(2) films on amorphous substrates as a function of vapour incident angle, substrate temperature and film thickness were investigated by scanning electron microscopy, x-ray pole figure and reflection high energy electron diffraction surface pole figure analyses. Results show that an anomalous [220] out-of-plane texture was preferred in CaF(2) films deposited on Si substrates at < 200?°C with normal vapour incidence. With an increase of the vapour incident angle, the out-of-plane orientation changed from [220] to [111] at a substrate temperature of 100?°C. In films deposited with normal vapour incidence, the out-of-plane orientation changed from [220] at 100?°C to [111] at 400?°C. In films deposited with an oblique vapour incidence at 100?°C, the texture changed from random at small thickness (5 nm) to biaxial at larger thickness (20 nm or more). Using first principles density functional theory calculation, it was shown that [220] texture formation is a consequence of energetically favourable adsorption of CaF(2) molecules onto the CaF(2)(110) facet.     

Improving hardness of biomedical Co-Cr by deposition of dense and uniform TiN films using negative substrate bias during reactive sputtering

This paper reports the deposition of a fully dense and uniform TiN film to improve the surface hardness of Co-Cr, particularly, by applying a negative substrate bias during reactive direct current (DC) sputtering. As the TiN film was deposited with a negative substrate bias voltage of 150 V, the microstructure of the films was shifted from a columnar to non-columnar one that was observed to have a dense, uniform and smooth surface. In addition, the preferred orientation was the (111) plane when the films were deposited with a negative substrate bias; however, the (200) plane when they were deposited without a substrate bias. The deposition of the dense and uniform TiN film resulted in a significant increase of the hardness of the Co-Cr. The TiN-deposited Co-Cr with a negative substrate bias showed a very high hardness of 44.7 ± 1.7 GPa, which was much higher than those of the bare Co-Cr (4.2 ± 0.3 GPa) and TiN-deposited Co-Cr without a negative substrate bias (23.6 ± 2.8 GPa).     

Effect of electron beam irradiation on structure and properties of SiCN thin films prepared by plasma assisted radio frequency magnetron sputtering

Silicon carbon nitride thin films were deposited on Si (100) substrate at room temperature by plasma assisted radio frequency magnetron sputtering. The bonding structure and properties of SiCN films irradiated by pulsed electron beams were studied by means of X-ray photoelectron spectroscopy and nano-indentation. The results showed that electron beam irradiation had a great effect on the structure and property of the films. Under sputtering gas pressure of 3.7 Pa, a transition from the (Si,C)N_x bonded structure to the (Si,C)₃N₄ bonded structure was found in the SiCN thin film with electron beam irradiation. At sputtering gas pressure of 6.5 Pa, the enhancement of hardness in the SiCN film after treatment with electron beam irradiation resulted from the promotion of the sp³-hybridization of carbons bonds.     

Effect of bias voltage on microstructure, mechanical and wear properties of Al-Si-N coatings deposited by cathodic arc evaporation

Al-Si-N coatings were deposited on tungsten carbide (WC-Co) and silicon wafer substrates using Cr and AlSi (12 at.% Si) alloy targets using a dual cathode source with short straight-duct filter in the cathode arc evaporation system. Al-Si-N coatings were synthesized under a constant flow of nitrogen, using various substrate bias voltages at a fixed AlSi cathode power. To enhance adhesive strength, the Cr/(Cr_xAl_ySi_z)N graduated layer between the top coating and the substrate was deposited as a buffer interlayer. The effects of bias voltage on the microstructure, mechanical and wear properties of the Al-Si-N films were investigated. Experimental results reveal that the Al-Si-N coatings exhibited a nanocomposite structure of nano-crystalline h-AlN, amorphous Si₃N₄ and a small amount of free Si and oxides. It was also observed that the deposition rate of as-deposited films gradually decreased from about 25.1 to 18.8 nm/min when the substrate bias was changed from − 30 to − 150 V. The XRD results revealed that h-AlN preferred orientation changed from (002) to (100) as the bias voltage increased. The maximum hardness of approximately 35 GPa was obtained at the bias voltage of −90 V. Moreover, the grain size was inversely proportional to the hardness of the film. Wear test results reveal that the Al-Si-N film had a lower coefficient of friction, between 0.5 and 0.7, than that 0.7 of the AlN film.     

Characterization and properties of CrN films deposited by ion-source-enhanced middle frequency magnetron sputtering

CrN films with deposition rates of 130-180 nm/min were deposited on Si (111) and carbamide alloy substrates by an ion-source-enhanced middle frequency magnetron sputtering system. Increasing of ion source voltages promoted the growth of CrN films with preferred orientation of (200). The deposited CrN films are composed of nanocrystalline particles with sizes of ∼20 nm embedded in polycrystalline matrix. The hardness of the CrN films increases from 1300 Kg/mm² without ion source bombardment to 2400 Kg/mm² with ion source voltages of 1000 V. Origins for the increasing of hardness can be attributed to dislocation strengthening and densification effects.     

Nanomechanical characterization of thermally evaporated Cr thin films — FE analysis of the substrate effect

We study the substrate effect on the deformation and hardness behaviour of chromium thin films using nanoindentation technique. Two different substrates namely Si (100) and AISI-304 SS are used in order to obtain a soft film on a hard substrate and a hard film on a soft substrate combination. Typical hardness variations for the two combinations are obtained. It is also observed that Cr thin films deposited on two different substrates deform distinctly. Radial cracks are found to develop in the case of Cr film on Si whereas circumferential cracks are produced in the case of Cr film on SS substrate. Using 2-D finite element analysis, it is found that the substrate not only affects the development of plastic zone but also the stress distribution in the films which results in observed distinct hardness and deformation behaviour.     

Effect of deposition angle on the structure and properties of pulsed-DC magnetron sputtered TiAlN thin films

This article reports the comparison of structure and properties of titanium aluminum nitride (TiAlN) films deposited onto Si(100) substrates under normal and oblique angle depositions using pulsed-DC magnetron sputtering. The substrate temperature was set at room temperature, 400 °C and 650 °C, and the bias was kept at 0, − 25, − 50, and − 80 V for both deposition angles. The surface and cross-section of the films were observed by scanning electron microscopy. It was found that as the deposition temperature increases, films deposited under normal incidence exhibit distinct faceted crystallites, whereas oblique angle deposited (OAD) films develop a kind of “tiles of a roof” or “stepwise structure”, with no facetted crystallites. The OAD films showed an inclined columnar structure, with columns tilting in the direction of the incident flux. As the substrate temperature was increased, the tilting of columns nearly approached the substrate normal. Both hardness and Young's modulus decreases when the flux angle was changed from α = 0° to 45° as measured by nanoindentation. This was attributed to the voids formed due to the shadowing effect. The crystallographic properties of these coatings were studied by θ-2θ scan and pole figure X-ray diffraction. Films deposited at α = 0° showed a mixed (111) and (200) out-of-plane orientation with random in-plane alignment. On the other hand, films deposited at α = 45° revealed an inclined texture with (111) orientation moving towards the incident flux direction and the (200) orientation approaching the substrate normal, showing substantial in-plane alignment.     

工艺参数对阴极电弧离子镀ZrN薄膜表面形貌及结构的影响

本文采用阴极电弧离子镀技术制备了ZrN膜层,研究了工作气压、偏压、弧流等工艺参数对ZrN膜层表面形貌和结构的影响,分别用扫描电镜(SEM)、X射线衍射仪(XRD)分析了膜层的表面形貌及相结构。结果表明:工作气压、偏压、弧电流等工艺参数对ZrN膜层的表面形貌有较大的影响,在本实验内适当提高N2压强、偏压以及在稳弧前提下降低弧流有利于减少大颗粒,改善ZrN膜层表面形貌,提高膜层综合性能;不同工艺参数下制备的ZrN膜层均具有典型的面心立方结构,工作气压和弧电流对ZrN膜层晶体生长方向的影响较小,偏压对晶体生长方向的影响显著,在20 V偏压下,晶体呈(200)面择优取向,继续提高偏压(100 V~300 V),晶体生长呈(111)面择优取向。