Lateral magnetic inhomogeneities in Co-Cr layers detected by FMR

Co-Cr layers deposited on Ge underlayers were investigated with ferromagnetic resonance (FMR). The thickness of the Co-Cr layers and the substrate temperature (T_s) during deposition were varied. Measurements with a vibrating sample magnetometer showed that an increase of T_s results in an increase of both the bulk saturation magnetization M_s and the perpendicular coercivity H_c^⊥. The FMR spectra, obtained with the applied field perpendicular to the sample, showed two resonances for all layers. The effective anisotropy field is positive for both resonances. The difference in effective anisotropy field does not change with thickness of the layer, but increases with increasing T_s. From this it is clear that the two resonances are not due to magnetic inhomogeneities in the growth direction, but must be due to lateral magnetic inhomogeneities. Inhomogeneities in composition, resulting in different values of M _s, or in geometric structure, resulting in different values of the demagnetizing factor N_d, are the most probable causes of the observed effects     

R.F. reactive sputter deposition of hydrogenated amorphous silicon carbide films

The preparation of hydrogenated amorphous silicon carbide films by r.f. reactive sputtering of a silicon target in Ar-CH₄ gas mixtures with and without an r.f. bias on the substrates was studied. Starting with a pure silicon target and increasing monotonically the CH₄ percentage from 0% to about 10%, films with 1 ⩾ x ⩾ 0 were obtained at decreasing deposition rates. After sputtering for some hours in methane-rich gas mixtures, carbon atoms were incorporated into the silicon target surface, probably as a result of atomic peening, and nearly stoichiometric SiC films were prepared by sputtering of such a target in pure argon. The different mechanisms of film formation, deposition rate, composition, hardness, friction coefficient and stresses in the films as functions of the partial pressure of methane and the value of the r.f. bias were investigated. The IR spectra offilms with different carbon contents were analysed. The greatest hardness was found for nearly stoichiometric SiC films deposited with a bias.     

R.F. plasma deposition of silicon nitride layers

A versatile r.f. plasma deposition system used to deposit high quality Si₃N₄ films at low temperature (200–350°C) is described. By introducing the reactant gases separately and reactively reducing the oxygen content of the system, films which exhibited very little oxygen contamination could be deposited. Rutherford backscaterring studies were used to evaluate the atomic composition of the films. The composition was related to other parameters such as the index of refraction, the etch rate and the deposition rate. The nitride layers described here were used successfully to anneal ion-implanted GaAs with negligible surface degradation.     

Magnetic and structural characteristics of ion beam sputter deposited Co-Cr thin films

-The magnetic and structural characteristics of ion beam sputter deposited Co82Cr18films were investigated. Films of between 1000A and 10,000A thickness were deposited on glass, titanium, chromium and amorphous Ta-W-Ni. The average angle of incidence of the sputtered species was normal to the substrate surface. Film orientation was determined by x-ray pole figure analysis. In films deposited on glass with thicknesses below 10,000A, the     

Influence of magnetizing parameters on the magnetic Barkhausennoise

Magnetic Barkhausen noise (MBN) measurements were made on a sample of pipeline steel as functions of magnetizing frequency and AC flux density in the sample. The observed MBN responses suggest a strong dependence on these magnetizing parameters. With increasing flux density in the sample, the MBN activity initially increases but finally begins to decrease at higher magnitudes of flux density. The MBN activity also increases with increasing magnetizing frequency. Pulse-height distribution analysis of the MBN waveforms suggests that the dependence of MBN activity on these magnetization parameters is more complex than appears from the rms voltage measurements     

Surface structural damage produced in InP(100) by R.F. plasma or sputter deposition

Rutherford backscattering detected at grazing angle under channeling conditions was employed to observe and quantify surface structural damage to InP(100) produced by dielectric deposition methods involving direct 13.56 MHz r.f. plasma exposure. Sputter deposition at any plasma power produced surface damage, to a maximum depth of about 30 Å at power densities within the range 0.25–2.2 W cm^?2. In contrast, damage due to plasma deposition was not observable at any plasma power density up to 0.32 W cm^?2 for InP substrates at either 250 or 31°C. This power level produced the high SiO₂ deposition rate of 1500 Å min^?1. Thus plasma deposition is particularly applicable to InP, whereas diode sputter deposition should be avoided for any application in which structural damage may be detrimental.     

The effects of incident angle on C-axis orientation in sputtered Co-Cr films

The effects of the incident angle of the sputtered atoms on the crystallographic orientation in the Co-Cr films have been investigated in detail. Specimen films 1000 - 2000 Å thick were prepared by the Facing Targets Sputtering (FTS) system. The specially designed mask was used for collecting only the sputtered particles with the quasi-coherent incidence to the substrate. When the films are prepared at relatively low argon gas pressures, the effect of incident angle is not so apparent and the well c-axis oriented films can be obtained for the incident angle below 45°. This result indicate that the surface diffusion may be dominant over the incident angle for attaining the desired crystallographic orientation in the films when they are prepared at low working gas pressures. Owing to the unique target/substrate layout, the plasma-free FTS system with low working gas pressures may have much larger flexibilities for preparing the well c-axis oriented Co-Cr films as compared with the conventional sputtering systems or the vacuum evaporation one.     

一种增磁装置在磁控射频溅射制备薄膜中的应用

为提高射频溅射成膜率,本文报道了一种配置于磁控溅射装置的射频(RF)增磁装置.基于此装置的实验结果表明,在不对原有装置作任何改动的情况下,在完全相同的溅射参数下,采用此装置可使射频溅射成膜率增大为原来的4倍左右.进而,该装置提供了一种能有效地节省溅射制备时间,改善薄膜结构的简便易行的新型手段.     

R.F. sputtering of plastics

This paper outlines the application of r.f. sputtering to plastic as a means of obtaining thinner dielectric layers with good electrical properties for use in the capacitor industry.The construction and characteristics of the sputtering system employed to obtain thin films of PTFE are described. A brief résumé of the differences observed between such films and conventional PTFE is included together with a short discussion of the observed electrical behaviour.     

Influence of additional magnetic field on plasma parameters in magnetron sputtering

With three additional magnetic rings being assembled outside the discharge room and connected with the magnetic field of the conventional unbalanced magnetron sputtering, a closed magnetic field configuration distribution had been formed in the whole discharge room and which can confine discharge plasma more effectively. The spatial distribution of the newly designed magnetic field configuration was simulated using the ANSYS software. Plasma potential, electron temperature, electron density and ion density in the discharge plasma were diagnosed by Langmuir probe and the optical emission line intensity ratios of Ar⁺/Ar and Cu⁺/Cu were studied by optical emission spectroscopy. The structure and morphology of the Cu films are measured by scanning electron microscopy. A comparative study of the new magnetic field configuration with the conventional unbalanced magnetic field configuration was conducted. The results showed that the application of the additional magnetic field can increase the plasma density, enhance the ionization degree of the sputtered Cu and decrease the plasma potential effectively. The characteristics of the deposited Cu film were also influenced by the new magnetic field configuration greatly.     

Influence of deposition parameters on preferred orientation of RF magnetron sputtered BST thin films

Ba_0.65Sr_0.35TiO₃ (BST) thin films have been deposited by radio frequency magnetron sputtering. The effects of the deposition parameters on the crystallization and microstructure of BST thin films were investigated by X-ray diffraction and field emission scanning electron microscopy, respectively. The crystallization behavior of these films was apparently affected by the substrate temperature, annealing temperature and sputtering pressure. The as-deposited thin films at room temperature were amorphous. However, the improved crystallization is observed for BST thin films deposited at higher temperature. As the annealing temperature increased, the dominant X-ray diffraction peaks became sharper and more intense. The dominant diffraction peaks increased with the sputtering pressures increasing as the films deposited at 0.37–1.2 Pa. With increasing the sputtering pressure up to 3.9 Pa, BST thin films had the (110) + (200) preferred orientation. Possible correlations of the crystallization with changes in the sputtering pressure were discussed. The SEM morphologies indicated the film was small grains, smooth, and the interface between the film and the substrate was sharp and clear.     

R.F.磁控溅射生成的氧化钨薄膜的性能

由于薄膜沉积过程中缺乏氧气,溅射得到的是化学配比偏离WO3的氧化钨薄膜,本文详细研究了不同电压下,R.F磁控溅射生成的不同化学配比的氧化钨薄膜的伏安循环特性;发现它们在一定电压范围内(1.15V到2.8V)都可产生着色现象.着色后对光的吸收是一致的.光的透过率显示电压超过某一值后,膜的变色能力减弱并消失.XRD显示本文所得氧化钨薄膜主要是非晶态的结构.     

Influence of bias voltage and sputter mode on the coating properties of TiAlSiN

Silicon offers promising opportunities to improve the characteristics of thin coatings. By adding silicon to TiAlN, the oxidation resistance as well as the tribological properties can be increased and improved. To analyze the influence of the silicon content on the coating properties of TiAlSiN, it is necessary to keep the ratio of the other coating elements constant by using the right target configuration. Within this study, TiAlSiN coatings were deposited on hot work steel AISI H11 by using magnetron sputtering (Cemecon CC800/9 sinox ML). This steel was previously plasma nitrided to increase the hardness and hence the carrying load of the substrate, avoiding shell egg effect during the analysis. Different sputter modes were used to analyze the possibility to produce TiAlSiN by utilizing a pure low conductive silicon target. The bias voltages were systematically varied to see their influence on the structure and chemical compositions of the coating which were investigated by means of scanning electron microscopy and energy dispersive X‐ray spectroscopy (EDX). Furthermore, the roughness of the surface of the coatings was measured by an optical three‐dimensional surface analyzer. The results of this study serve as a basis for further investigations regarding the variation of the silicon content of TiAlSiN coatings.     

Effects of the AsCl3 mole fraction and the substrate orientation on the electrical parameters of heteroepitaxial indium arsenide layers

The effects of the mole fraction of AsCl₃ and the orientations ((111)A, (111)B and (100)) of the GaAs substrate on the current carrier concentration and the mobility of InAs layers are studied. The experimental data show that the electrical parameters can be controlled by varying the AsCl₃ mole fraction and that the orientation effect depends on the deposition temperature.     

Influence of thin platinum layer on the magnetic properties of multiple layers of CVD cobalt thin films

This paper presents the results obtained on the multiple layers of cobalt (Co)/platinum (Pt) and cobalt (Co)/platinum (Pt)/cobalt (Co) on the oxidised silicon substrate. The cobalt layers were deposited by metal-organic chemical vapour deposition on oxidised-silicon substrates at 450?°C, in H₂ ambient with 2-torr processing pressure. The platinum layers were deposited by E-beam evaporation in a separate vacuum system. The magnetic properties of Co/Pt/Co and Co/Pt multilayer were compared with the single cobalt layers of similar thicknesses on the oxidised silicon substrate. From the hysteresis loops it was observed that thin cobalt layers on oxidised-silicon substrate shows hard magnetic property with coercivity H _c values of 360 Oe and 500 Oe respectively for the 30- and 15-nm cobalt layers. The multiple layers of Co/Pt/Co and Co/Pt of cobalt thickness 15- and 30-nm with platinum 1.5-nm spacer-layer show significant change in magnetic properties (i.e. coercivity H _c and magnetisation M _s ) and, gave soft magnetic properties with H _c values 51 and 49 Oe respectively, which are significantly less than the H _c values of single cobalt layers on oxidised silicon. Also, single and multiple layers cobalt with platinum were annealed and compared with the as-deposited layer structures. From the microstructure analysis by SEM, and AFM it was found that the single and multilayer had similar roughness. Magnetic images were observed by MFM and analyzed in terms of domain structure.     

The domain structure and magnetic properties of Co-Cr, Mo films

The magnetic properties of Co-Cr and Co-Mo films prepared by d.c. triode sputtering are discussed. The films are found to have perpendicular magnetisation in certain composition ranges. The magnetic domain structure of the films as observed by Lorentz electron microscopy is interpreted in terms of the deposition parameters and the properties of the films. In particular the microstructure of the films is seen to have an overwhelming influence on the domain structure.