多元氮化物薄膜及其沉积工艺对NiTi记忆合金性能和组织的影响

采用真空阴极电弧沉积技术,在NiTi记忆合金表面沉积了TiAlBN和TiAlCrFeSiBN多元膜和TiN薄膜,研究了薄膜成份及沉积工艺对NiTi合金性能和组织的影响.结果表明,在NiTi合金表面沉积TiAlBN和TiAlCrFeSiBN多元膜和TiN薄膜均可降低合金在Hank溶液中的Ni溶出速率,其中多元膜的Ni溶出速率最小;提高偏压对沉积了TiAlBN多元膜的NiTi合金的Ni溶出速率无明显影响,但使沉积了TiAlCrFeSiBN膜的NiTi合金的Ni溶出速率降低.在TiAlBN和TiAlCrFeSiBN多元膜表面存在较多细小的钛滴和孔隙,钛滴与薄膜基体之间的融合良好;在TiN薄膜表面存在一些大钛滴和孔隙,钛滴与薄膜基体之间的融合不好.镀膜后,NiTi基体的加热相变点移向低温区,其幅度与薄膜成份及沉积工艺有关,提高偏压使沉积了两种多元膜的NiTi基体的相变点移动幅度增大,但却使沉积了TiN膜的NiTi基体的相变点的移动幅度减小.镀膜过程均使NiTi中的M体尺寸增大.     

Dependence of the electrical and optical properties on the bias voltage for ZnO:Al films deposited by r.f. magnetron sputtering

Aluminum-doped zinc oxide (ZnO:Al) thin films were deposited on glass, polycarbonate (PC), and polyethylene terephthalate (PET) substrates by r.f. magnetron sputtering. The substrate dc bias voltage varied from 0 V to 50 V. Structural, electrical and optical properties of the films were investigated. The deposition rate of ZnO:Al films on glass substrate initially increased with the bias voltage, and then decreased with further increasing bias voltage. It was found that the best films on glass substrate with a low as 6.2 × 10^− 4 Ω cm and an average transmittance over 80% at the wavelength range of 500-900 nm can be obtained by applying the bias voltage of 30 V. The properties of the films deposited on polymer substrate, such as PC and PET, have a similar tendency, with slightly inferior values to those on glass substrate.     

TC4钛合金表面电弧离子镀TiN/CrN纳米多层薄膜研究

用电弧离子镀技术在TC4钛合金基体上通过改变偏压制备了4组TiN/CrN薄膜,对薄膜的表面形貌、厚度、相结构、硬度、膜基结合力和摩擦系数等组织、性能进行了测试表征。结果表明,薄膜是由TiN相和CrN交替叠加构成的纳米多层薄膜,薄膜的调制周期为60 nm,总的厚度约为480 nm。与基体钛合金相比,镀膜后样品的表面性能与偏压幅值密切相关并有显著提高:显微硬度从基体的3 GPa提高到16.5~24.7 GPa;摩擦系数从基体的0.35大幅度降低到0.14~0.17;薄膜与基体结合牢固,膜基临界载荷在60~80N之间。经电弧离子镀TiN/CrN纳米多层薄膜处理后,TC4钛合金可以满足沙粒和尘埃磨损条件下的耐磨性能要求。     

Deposition,structure and hardness of Ti–Cu–N hard films prepared by pulse biased arc ion plating

In this work, Ti–Cu–N hard nanocomposite films were deposited on 304 stainless steel (SS) substrate by using pulse biased arc ion plating system with Ti–Cu alloy target. The effects of negative substrate pulse bias voltages on chemical composition, structure, morphology and mechanical properties were investigated. The composition and structure of these films was found to be dependent on the pulse bias, whereas the pulse biases put little influence on hardness of these films. The XPS spectra of Cu 2p showed that obtained peak values correspond to pure metallic Cu. Cu content in Ti–Cu–N nanocomposite films changed with pulse bias voltage. In addition, X-ray diffraction analysis showed that a pronounced TiN (111) texture is observed under low pulse bias voltage while it changed to TiN (220) orientation under high pulse bias voltage. Surface roughness of the Ti–Cu–N nanocomposite films achieved to the minimum value of 0.11 μm with the negative pulse bias voltage of −600 V. The average grain size of TiN was less than 17 nm. The mechanical properties of Ti–Cu–N hard films investigated by nanoindentation revealed that the hardness was about 22–24 GPa and the hardness enhancement was not obtained.     

Deposition,structure and hardness of Ti–Cu–N hard films prepared by pulse biased arc ion plating

In this work, Ti–Cu–N hard nanocomposite films were deposited on 304 stainless steel (SS) substrate by using pulse biased arc ion plating system with Ti–Cu alloy target. The effects of negative substrate pulse bias voltages on chemical composition, structure, morphology and mechanical properties were investigated. The composition and structure of these films was found to be dependent on the pulse bias, whereas the pulse biases put little influence on hardness of these films. The XPS spectra of Cu 2p showed that obtained peak values correspond to pure metallic Cu. Cu content in Ti–Cu–N nanocomposite films changed with pulse bias voltage. In addition, X-ray diffraction analysis showed that a pronounced TiN (111) texture is observed under low pulse bias voltage while it changed to TiN (220) orientation under high pulse bias voltage. Surface roughness of the Ti–Cu–N nanocomposite films achieved to the minimum value of 0.11 μm with the negative pulse bias voltage of ?600 V. The average grain size of TiN was less than 17 nm. The mechanical properties of Ti–Cu–N hard films investigated by nanoindentation revealed that the hardness was about 22–24 GPa and the hardness enhancement was not obtained.     

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.     

The influence of substrate bias in I-PVD process on the properties of Ti and Al alloy films

The effects of substrate bias power on the microstructure, physical and electrical properties of thin Ti films prepared by ionized physical vapor deposition (I-PVD) process were studied. The influence of Ti underlayer with substrate bias power ranging from 0 to 400 W on the subsequent TiN/AlCu films deposited by conventional PVD process in a multilayer structure was further investigated. Decreasing substrate bias power led: (1) better Ti(002) texture, smoother surface, and lower resistivity in Ti films, and (2) better Al(111) texture, narrower grain size distribution, smoother final surface, better-defined TiN/AlCu interface, and lower residual stress in AlCu alloy films in the corresponding Ti/TiN/AlCu stacks. In both cases, lower substrate bias power resulted in films with desirable microstructures and properties, compared to higher bias powers, for use as Al-based interconnects in IC manufacturing.     

反应溅射TiN纳米晶薄膜的结构特征和耐蚀性

利用直流反应溅射技术在不锈钢和硅基体上沉积了TiN纳米晶薄膜,采用场发射扫描电镜(FESEM)、X射线衍射(XRD)和电化学阻抗谱(EIS)技术研究了薄膜的表面形貌、相结构和耐蚀性与偏压的关系。结果表明,TiN薄膜的表面结构明显取决于所施加的偏压,适当提高偏压有利于获得细小、均匀、致密和光滑的膜层。XRD分析发现,TiN薄膜为面心立方结构,其择优取向为(111)面。实验显示,对应0V和-35V偏压的薄膜为欠化学计量比的,而偏压增加至-70V和-105V时的薄膜为化学计量比的TiN。EIS结果表明,较高偏压下的TiN薄膜几乎在整个频率范围内均表现为容抗特征,其阻抗模值明显高于低偏压下的膜层,这主要与较高偏压下的薄膜具有相对致密的微结构有关。较低偏压的TiN薄膜因结构缺陷较多其耐蚀性低于基体不锈钢。EIS所揭示的薄膜结构特征与FESEM观测结果一致。可见,减少穿膜针孔等结构缺陷有利于改善反应溅射TiN纳米晶薄膜耐蚀性。     

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.     

Cathodic arc plasma deposited TiAlSiN thin films using an Al-15 at.% Si cathode

Thin films of TiAlSiN were deposited on SKD 11 tool steel substrates using two cathodes, of Ti and Al-15 at.% Si, in a cathodic arc plasma deposition system. The influence of AlSi cathode arc current and substrate bias voltage on the mechanical and structural properties of the films was investigated. The TiAlSiN films had a multilayered structure in which nanocrystalline cubic TiN layers alternated with nanocrystalline hexagonal AlSiN layers. The hardness of the films decreased with the increase of the AlSi cathode arc current. The hardness of the films also decreased as the bias voltage was raised from − 50 V to − 200 V. The maximum hardness of 43 GPa was observed at the films deposited at the pressure 0.4 Pa, Ti cathode arc current 55 A, Al cathode arc current 35 A, temperature 250 °C and bias voltage of − 50 V.     

Deposition of TiN coatings on shape memory NiTi alloy by plasma immersion ion implantation and deposition

An investigation has been carried out to study the effect of pulse negative bias voltage on the morphology, microstructure, mechanical, adhesive and tribological properties of TiN coatings deposited on NiTi substrate by plasma immersion ion implantation and deposition. The surface morphologies were relatively smooth and uniform with lower root mean square values for the samples deposited at 15 kV and 20 kV negative bias voltages. X-ray diffraction results demonstrated that the pulse negative bias voltage can significantly change the microstructure of TiN coatings. The intensity of TiN(220) peak increased with the increase of negative bias voltage in the range of 5-20 kV. When the negative bias voltage increased to 30 kV, the preferred orientation was TiN(200). Nanoindentation test indicates that hardness and elastic modulus increased with the increase of the negative bias voltage (5 kV, 15 kV and 20 kV), and then dropped sharply at 30 kV. The adhesion between the TiN and NiTi alloy and tribological properties of TiN coated NiTi alloy depend strongly on the bias voltage parameter; the sample deposited at 20 kV possesses good adhesion strength and excellent tribological property.     

纳米结构TiN薄膜的制备及其摩擦学性能

在室温条件下,用磁过滤等离子体装置在单晶硅基底上制备了纳米结构TiN薄膜分析了薄膜的表面形貌、晶体结构,测量了TiN薄膜的硬度,研究了基底偏压对薄膜结构性能的影响.结果表明,用此方法制备的TiN薄膜表面平整光滑,颗粒尺寸为50～80 nm;随着基底偏压的增大薄膜发生(111)面的择优取向随着偏压的提高,薄膜的颗粒度稍有增大,摩擦系数增大,偏压提高,晶面在较密排的(111)面有强烈的择优取向,硬度也有所增大.在其它条件相同的情况下载荷越大,摩擦系数越大.不起用磁过滤等离子体法制备的纳米结构TiN薄膜具有较低的摩擦系数(0.14～0.25).     

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).     

Influence of substrate temperature and bias voltage on the optical transmittance of TiN films

Titanium nitride (TiN) thin films were prepared by means of reactive DC sputtering on quartz and sapphire substrates. Structural, electrical and optical effects of deposition parameters such as thickness, substrate temperature, substrate bias voltage were studied. The effect of substrate temperature variations in the 100-300°C range and substrate bias voltage variations in the 0-200 V DC range for 45-180 nm thick TiN films were investigated. Temperature-dependent electrical resistivity in the 100-350 K range and optical transmission in the 300-1500 nm range were measured for the samples. In addition, structural and morphological properties were studied by means of XRD and STM techniques.The smoothest surface and the lowest electrical resistivity was recorded for the optimal samples that were biased at about V_s=−120 V DC. Unbiased films exhibited a narrow optical transmission window between 300 and 600 nm. However, the transmission became much greater with increasing bias voltage for the same substrate temperature. Furthermore, it was found that lower substrate temperatures produced optically more transparent films.Application of single layers of MgF₂ antireflecting coating on optimally prepared TiN films helped increase the optical transmission in the visible region to more than 40% for 45 nm thick samples.     

Influence of substrate bias voltage on properties of Pt thin films deposited by non-mass separated ion beam deposition method

Pt thin films were deposited on Si substrates by applying a negative substrate bias voltage using a non-mass separated ion beam deposition method. The effect of the substrate bias voltage on the properties of the deposited films was investigated. In the case of Pt thin films deposited without the substrate bias voltage, a columnar structure and small grains were observed. The electrical resistivity of the deposited Pt films was very high (49.3 ± 0.65 µΩ cm). By increasing the substrate bias voltage, no clear columnar structure was observed. At the substrate bias voltage of − 75 V, the resistivity of the Pt film showed a minimum value of 16.9 ± 0.2 µΩ cm closed to the value of bulk (10.6 µΩ cm).     

阴极电弧沉积TiN薄膜研究

对真空阴极电弧沉积TiN装饰膜的沉积工艺和膜层性能的关系进行了研究。结果表明:适当选择N_2分压和负偏压对于改善基体表面离子轰击清洗效果、减少液滴分布、保证膜层颜色和提高膜层耐蚀性至关重要。另外,X射线织构分析表明:(220)织构随负偏压加大而增加,而(111)织构则随N_2分压增大而增加,这可由离子轰击诱导织构效应解释。     

Influence of Substrate Negative Bias on Structure and Properties of TiN Coatings Prepared by Hybrid HIPIMS Method

TiN coatings were deposited using a hybrid home-made high power impulse magnetron sputtering(HIPIMS)technique at room temperature.The effects of substrate negative bias voltage on the deposition rate,composition,crystal structure,surface morphology,microstructure and mechanical properties were investigated.The results revealed that with the increase in bias voltage from-50 to-400 V,TiN coatings exhibited a trend of densification and the crystal structure gradually evolved from(111) orientation to(200)orientation.The growth rate decreased from about 12.2 nm to 7.8 nm per minute with the coating densification.When the bias voltage was-300 V,the minimum surface roughness value of 10.1 nm was obtained,and the hardness and Young's modulus of TiN coatings reached the maximum value of 17.4 GPa and 263.8 GPa,respectively.Meanwhile,the highest adhesion of 59 N was obtained between coating and substrate.     

Bias voltage dependence properties of cadmium oxide films deposited by d.c. reactive magnetron sputtering

Cadmium oxide films were grown on glass substrates using d.c. reactive magnetron sputtering technique by sputtering from a metallic cadmium target in an oxygen partial pressure of 1×10^–3 mbar under various substrate bias voltages. The substrate bias voltage significantly influences the crystallographic structure of the deposited films. The influence of substrate bias voltage on the electrical and optical properties of the films was systematically studied. The films formed at a substrate temperature of 473 K and bias voltage of –80 V showed an electrical resistivity of 1×10^–3 cm, optical transmittance of 86%, optical band gap of 2.47 eV and a figure of merit of 7×10^{–3 –1}.     

Effect of bias voltage on microstructure and mechanical properties of nanocrystalline TiN films deposited by reactive magnetron sputtering

Nanocrystalline TiN films deposited under various bias voltages have been prepared by a reactive magnetron sputtering. The effect of bias voltage on the microstructural morphologies of the TiN films was characterized by FE-SEM and AFM. The texture of the TiN films was characterized by XRD. It is also observed that the crystallite size decreases with increasing bias voltages. However, rms roughness increases with increasing bias voltages. The changes in roughness and crystallite size in the TiN thin films are due to one or a combination of factors such as resputtering, ion bombardment, surface diffusivity and adatom mobility; the influence of each factor depends on the processing conditions.     

Effect of process parameter changes on the composition of magnetron sputtered and evaporated TiN and AlN films measured by UHV in-situ techniques

TiN and AlN films are deposited on HSS steel substrates in an ultrahigh vacuum magnetron system equipped with in-situ Auger electron spectroscopy (AES) and mass spectrometric sensors for plasma diagnostics. The composition of TiN_x coatings is measured by AES as a function of the N₂ pressure, the bias voltage, and the d.c. power. The flux of ionic particles impinging on the substrate surface and their energies are determined by a quadruple mass analyzer mounted behind a hole in the substrate. In addition, the reactivity of neutral nitrogen molecules in a reactive evaporation process is measured by a quartz crystal microbalance.