非对称双极脉冲磁控溅射沉积氮化铬铝涂层的微观结构和硬度

利用非对称双极脉冲磁控溅射技术,双极分别接纯铬靶和纯铝靶,通过调整两靶的功率,以反应溅射的方式沉积不同铬铝比的氮化铬铝涂层。研究不同Al含量的氮化铬铝涂层的结构和硬度。所获得的涂层依次为Cr0.95Al0.05N、Cr0.9Al0.1N、Cr0.83Al0.17N和Cr0.75Al0.25N,均为B1NaCl结构,(220)为主要的织构取向。随着涂层中Al含量的增加,涂层表面突起的尺寸逐渐降低,涂层趋于光滑致密;低Al含量涂层为柱状晶结构,随Al含量提高,涂层结构更加致密,并向等轴晶结构转变。涂层硬度随Al含量的提高先增加后降低,Cr0.83Al0.17N涂层表现出最高的硬度,维氏硬度达到33GPa以上。     

反应磁控溅射碳化铪薄膜的微结构与力学性能

为满足不同加工方式和加工条件下刀具对涂层的特殊要求,获得硬度高和耐摩擦性能优异的刀具涂层,采用反应磁控溅射方法制备了一系列不同碳含量的碳化铪薄膜。利用EDX,XRD,SEM,AFM和微力学探针表征了薄膜的微结构和力学性能,研究了C2H2分压(Ar和C2H2混合气体)对薄膜成分、相组成、微结构以及硬度和弹性模量的影响。结果表明,反应磁控溅射可以方便地制备碳化铪薄膜,但是,只有在C2H2分压为混合气体总压约3.0%附近很窄的范围内才可获得高硬度和高弹性模量的单相碳化铪薄膜,其最高硬度和弹性模量分别为27.9 GPa和255 GPa;低C2H2分压下所得薄膜由金属Hf和HfC两相组成,硬度较低;而过高的C2H2分压将导致薄膜形成非晶态,其硬度和弹性模量亦随之降低。     

Deposition pressure and rate effects on the microstructure and magnetic properties of sputtered tape media

Sputtered magnetic tape media were prepared by DC magnetron sputtering on polyimide substrates at different deposition conditions. The structure, texture and magnetic properties of the sputtered films were systematically studied using transmission electron microscopy, X-ray diffraction and alternating gradient magnetometer. The microstructure of sputtered media is greatly influenced by the deposition conditions, such as deposition pressure and rate. High sputtering pressure and slow deposition rate produced high coercivity and low delta M films. The sputtered tape media have the desired grain segregation structure which is essential for low-noise media fabrication. X-ray diffraction analysis revealed that the stress of film is closely related to the deposition pressure. The stress of the film stack can be tuned for specific applications and good magnetic properties can be obtained under optimized deposition condition.     

Effect of thermal annealing on Ni/Au contact to a-InGaZnO films deposited by dc sputtering

We deposited Ni (15 nm)/Au (30 nm) layers on a-InGaZnO in order to produce low-resistance ohmic contacts by using a dc sputtering method. The samples were annealed at various temperatures for 5 min in Ar ambient. The electrical and the structural properties of the Ni/Au contact to a-InGaZnO were investigated. According to the current-voltage measurements, both the as-deposited and low-temperature annealed samples showed an ohmic behavior. The specific contact resistance of the as-deposited sample was 4.1 × 10^− 5 Ω cm², which was the lowest value. Further increasing the temperature above 400 °C led to an increase in the specific contact resistance. This is due to the chemical intermixing and formation of the oxide in the contact interface caused by the post-growth thermal annealing.     

Investigations on TlBa2Ca2Cu3Ox superconducting thin films formation on LaAlO3 substrate

Investigations on pure superconducting phase TlBa₂Ca₂Cu₃O_x (Tl-1223) thin films formation, of about 100-125 nm in thickness, on (001) LaAlO₃ single crystal substrate, were made using radio-frequency sputtering deposition of Ba₂Ca₂Cu₃O_x precursor films and ex-situ thallination in sealed quartz tube. The precursor films were thallinated under different conditions of partial oxygen pressure, temperature, time and y thallium source content using unreacted pellets of composition Tl_yBa₂Ca₂Cu₃O_x. In all cases, strongly c-oriented multiphase films were obtained. A correlation between the Tl-1223 phase purity and the precursor film conditions of thallination is established. Temperature and time of thallination as well as the thallium source content and the partial pressure of oxygen play a key role in the quality of the obtained film. The films' onset temperature of the superconducting transition ranges between 90 and 103 K. It is shown that the best samples can be obtained from a dense precursor film and relatively medium thallination time.     

Electron energy loss spectroscopy of nano-scale CrAlYN/CrN-CrAlY(O)N/Cr(O)N multilayer coatings deposited by unbalanced magnetron sputtering

The nano-scale chemical distribution and microstructure of a nitride based wear and oxidation resistant coating prepared by unbalanced magnetron sputtering was investigated. The coating consisted of multilayers of CrAlYN/CrN with a partially oxidised CrAlY(O)N/Cr(O)N oxy-nitride surface layer. The multilayer period of both the nitride and oxy-nitride layers was 3.8 ± 0.2 nm. Nano-scale chemical analysis and imaging was performed using sub-nanometer resolution electron energy loss spectroscopic profiling in a spherical aberration corrected scanning transmission electron microscope. Experimentally determined fine edge structure in electron energy loss spectra were in good agreement with theoretically determined spectra, calculated using electron density functional theory. This analysis indicated the CrN layers to be near stoichiometric with a relative Cr/N ratio of 1.05 ± 0.1 while for the CrAlYN layers the best match between the direct chemical analysis and the simulated edges was (Cr_0.5Al_0.5)N. A diffuse interface, ∼ 1 nm wide was observed between the CrAlYN and CrN layers. For the outermost oxy-nitride layer, the chromium to nitrogen ratio remains approximately constant though out the layer, while the aluminium decreases as a function of increasing oxygen content.     

Characteristics of highly orientated BiFeO3 thin films on a LaNiO3-coated Si substrate by RF sputtering

BiFeO₃ (BFO) films were grown on LaNiO₃-coated Si substrate by a RF magnetron sputtering system at temperatures in the range of 300-700 °C. X-ray reflectivity and high-resolution diffraction measurements were employed to characterize the microstructure of these films. For a substrate temperature below 300 °C and at 700 °C only partially crystalline films and completely randomly polycrystalline films were grown, whereas highly (001)-orientated BFO film was obtained for a substrate temperature in the range of 400-600 °C. The crystalline quality of BFO thin films increase as the deposition temperature increase except for the film deposited at 700 °C. The fitted result from X-ray reflectivity curves show that the densities of the BFO films are slightly less than their bulk values. For the BFO films deposited at 300-600 °C, the higher the deposition temperature, the larger the remnant polarization and surface roughness of the films present.     

Enhanced conductivity of aluminum doped ZnO films by hydrogen plasma treatment

Aluminum doped zinc oxide (AZO) thin films prepared by radio-frequency (RF) magnetron sputtering at various RF power were treated by hydrogen plasma to enhance the characteristics for transparent electrode applications. The hydrogen plasma treatment was carried out at 300 °C in a plasma enhanced chemical vapor deposition system. X-ray diffraction analysis shows that all AZO films have a (002) preferred orientation and film crystallinity seems no significant change after plasma treatment. The plasma treatment not only significantly decreases film resistivity but enhances electrical stability as aging in air ambient. The improved electrical properties are due to desorption of weakly bonded oxygen species, formation of Zn-H type species and passivation of deep-level defects during plasma treatment.     

Growth and characteristics of ZnO films on growth side of freestanding diamond substrate dependent on buffer layer thickness

We report the growth and properties of highly c-axis oriented ZnO films, by radio-frequency magnetron sputtering, on the growth side of freestanding chemical vapor deposited diamond film-substrate. Low-temperature ZnO buffer layer is required for the formation of continuous ZnO films. The morphology, structure, and optical properties of the ZnO films deposited are strongly dependent on the thickness of the buffer layer. The optimized thickness of ZnO buffer layer is about 10 nm to realize high-quality ZnO films having small compressive stress and high intensity ultraviolet emission. The ZnO/diamond (growth side) system is available for the applications in numerous fields, especially for high performance surface acoustic wave devices.     

Effect of high-energy electron beam irradiation on the properties of AZO thin films prepared by rf magnetron sputtering

We investigated that high-energy electron beam irradiation (HEEBI) performed in air at room temperature affected remarkably the properties of Al-doped ZnO (AZO) films grown on SiO₂ substrates by radio frequency magnetron sputtering techniques. Hall and photoluminescence measurements revealed that the n-type conductivity was preserved in HEEBI treated films with low dose up to 10¹⁵ electrons/cm² and converted to p-type conductivity with further increase in the amount of dose. X-ray photoelectron spectroscopy confirmed the conversion of conductivity by showing that in-diffusion of O₂ from the ambient as well as out-diffusion of Zn from the films took place as a result of HEEBI treatment at high dose of 10¹⁶ electrons/cm². X-ray diffraction analysis indicated that all as-grown films were found to have compressive stress, which was enhanced by HEEBI treatment with the increase of doses. It was also found that worse crystallinity with a smaller grain size was observed in HEEBI treated films with a higher dose, which was correlated with rougher surface morphologies of films observed by an atomic force microscope.