磁控溅射氮分压对Nb-Si-N薄膜结构和性能的影响

用反应磁控溅射法在不同的氮分压下沉积了Nb-Si-N薄膜.结果表明：Nb-Si-N膜的成分、结构和性能随氮分压的改变而不同.随氮分压的增加,Nb-Si-N膜的Nb/Si比和表面粗糙度减小;薄膜的电阻值和微硬度增加.Nb-Si-N膜的结构为纳米晶NbN与类似Si3N4非晶相组成的纳米复合结构,且随着氮分压的增加,Nb-Si-N膜的非晶倾向增强,晶粒尺寸减小.     

Preparation and properties of SiCN diffusion barrier layer for Cu interconnect in ULSI

SiCN thin films and Cu/SiCN/Si structures were fabricated by magnetron sputtering. And some samples underwent the rapid thermal annealing(RTA) processing. The thin-film surface morphology, crystal structure and electronic properties were characterized by atomic force microscopy(AFM), X-ray diffractometry(XRD), Fourier transform infrared transmission(FTIR) and four-point probe(FPP) analyses. The results reveal the formation of complex networks among the three elements, Si, C and N, and the existence of different chemical bonds in the SiCN films, such as Si-C, Si-N, C-N and C=N. The as-deposited SiCN thin films are amorphous in the Cu/SiCN/Si structures and have good thermal stability, and the SiCN thin films are still able to prevent the diffusion reaction between Cu and Si interface after RTA processing at 600 ℃ for 5 min.     

Exceptions to the microstructure zone model revealed by the reactive d.c. magnetron sputter deposition of δ-TiNx thin films

This paper deals with the influence of the nitrogen flow rate on the microstructure of δ-TiN_x films prepared by d.c. magnetron sputtering. The δ-TiN_x films were prepared under decreasing nitrogen flow rates to obtain nitrogen contents in the films ranging from x=0.99 to 0.95. Ion bombardment of the films was negligible in these experiments.

Some films prepared under deposition conditions which typically result in a fine-grain (about 0.1 μm) transition zone microstructure exhibit a “large”-grain (about 1 μm) zone III microstructure. It has been demonstrated that there exists a narrow area of nitrogen flow rate for which the microstructure of the films does not agree with the zone model. The large-grain films are stress free. The nitrogen content in the films containing large grains is x=0.97. All deposition conditions except the nitrogen flow rate were kept constant in this experiment. Chemical energy dissipated during the reactive process can explain the observed effects.     

高迁移率的钛掺杂氧化铟薄膜在晶硅/非晶硅异质结电池上的应用研究

采用钛掺杂氧化铟旋转靶制备透明导电薄膜应用在晶硅/非晶硅异质结电池上。在不同氧含量下,研究钛掺杂氧化铟薄膜(T100薄膜)的光电性能,同时对比分析ITO薄膜。在电镜下T100薄膜呈现出柱状结构,并且展示出优异的光学性能。T100薄膜最大载流子迁移率可以达到75.6 cm~2·(V·s)^-1。相比于ITO薄膜,T100薄膜具有优异的电学传导和透光率,因此在异质结电池量产线上电池转换效率可以实现0.26%的提升。     

Relation of deposition conditions of Ti-N films prepared by d.c. magnetron sputtering to their microstructure and macrostress

A systematic study of the relation of the deposition conditions of Ti-N films prepared by d.c. magnetron sputtering to their microstructure and macrostress has been performed using two sets of -Ti(N) and δ-TiN films. The variable parameter in the deposition was the combined parameter S_E representing the energy delivered to the growing film.

The threshold energy S_Etr necessary for the transition from zone I to zone T of Thornton's structural zone model was investigated for both -Ti(N) and δ-TiN films. S_Etr for δ-TiN films is about one order of magnitude higher (S_E = 0.9 MJ cm^-3) than for -Ti(N) films (S_E = 0.15 MJ cm^-3) according to X-ray diffraction. This finding can be explained by difference in the melting temperature T_m of TiN T_m = 3200 K) and that of Ti T_m = 1930 K). Values of the macrostress of Ti-N films as a function of S_E are also given.     

Structural and mechanical properties of amorphous silicon carbonitride films prepared by vapor-transport chemical vapor deposition

The deposition of amorphous silicon carbonitride (a-SiCN:H) films has been successfully achieved through an in-house developed vapor-transport chemical vapor deposition (VT-CVD) technique in a nitrogenated atmosphere. Polydimethylsilane (PDMS) was used as a single-source precursor for both silicon and carbon, while NH₃ was mixed with argon to ensure the in-situ nitrogenation of the films. The chemical bonding and the atomic composition of the a-SiCN:H films were systematically investigated, as a function of their N content, by means of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). AFM was used to obtain 2-D and 3-D views of the films. The mechanical properties [(hardness (H) and Young's modulus (E)] of the freshly prepared films were investigated by the nanoindentation technique. It is shown that by controlling the NH₃/Ar gas flow ratio in the reactor, a-SiCN:H films with various N contents [(0-27) at.% range] are achieved. On the microstructural level, the increase incorporation of N in the a-SiCN:H films is found not only to lead to C atom substitution by N atoms in the local Si-C-N environment but also to an enhanced incorporation of hydrogen bonded to both Si and N. Furthermore, the increase incorporation of N in the a-SiCN:H films resulted in an increase of the average R_rms surface roughness from 4 to 12 nm. Moreover, the films became porous with pore size and density increase as a result of increasing N at.%. Ultimately, both H and E of the a-SiCN:H films were found to be sensitive to their N content, as they decrease (from ~ 17 GPa and 160 GPa to ~ 13 GPa and 136 GPa, respectively) when the N content is increased from 0 to 27 at.%. The formation of Si-N, Si-H, and N-H bonds at the detriment of the more stiff Si-C bonds is thought to account for the observed lowering of the mechanical properties of the a-SiCN:H films as their N content increased.     

Study on high-temperature oxidation behaviors of Cr–Si–N films

The high-temperature oxidation behavior of CrN and Cr–Si–N films was investigated. These films were deposited on STS 304 substrates by a hybrid deposition system with arc ion plating (AIP) and DC magnetron sputtering method using separate Cr (99.99%) and Si (99.99%) targets in a gaseous mixture of Ar and N₂. Good oxidation resistance of the CrN film was further improved by the incorporation of Si into the CrN film. The oxidation products of the Cr–Si–N film were Cr₂O₃ and amorphous SiO₂, which were gradually formed by the outward diffusion of Cr, Si, and N as well as the inward diffusion of oxygen. The oxidation kinetics of the specimen showed parabolic behavior, indicating that the diffusion process prevailed during oxidation. The oxidation activation energies for CrN, CrSi_0.10N, and CrSi_0.15N coatings are 303.8, 316.4, and 333.9 kJ/mol, respectively.     

Microstructure and mechanical properties of Ti 45Al 5Nb + (0–0.5C) sheets

The possible application of gamma titanium aluminides in aerospace industry requires a detailed understanding of the microstructure–property relationship of sheets made from this material. This paper reports the mechanical properties of sheets up to 1000 °C, based on alloy concepts with high Nb concentrations and small additions of C. Sheets were manufactured by rolling powder metallurgical compacts with compositions Ti 45Al 5Nb and Ti 45Al 5Nb 0.5C. The microstructures of both sheets are “near gamma” and consist of γ-TiAl and ₂-Ti₃Al phases. The texture of both phases is very weak. The strengths levels are very high and that of the C-containing sheet exceeds that of the C-free material at RT by 200 MPa. The mechanical properties of Ti 45Al 5Nb are independent of the direction in the sheet, in the whole temperature range from RT to 1000 °C. However, for the C-containing sheet this is true only in the upper temperature range.     

Low friction composite coating of CrxSiy/MoS2 on steel

The manufacture of the system tool steel/intermediate layer of Cr_xSi_y/low friction MoS₂ film was achieved by r.f. magnetron sputtering. The substrate material was X100CrMoV51 with a surface roughness of R_z<100 nm and average roughness of R_a<10 nm. The intermediate layers of Cr₃Si, CrSi, and CrSi₂ varied in film thickness between 150 and 300 nm, and the MoS₂ film was 300 or 600 nm thick. The films, deposited without a substrate heating, were amorphous, as shown by X-ray diffraction, and homogeneous in chemical composition (determined by secondary ion mass spectrometry and Auger electron spectroscopy). The Cr_xSi_y films corresponded in chemical composition to that of the target material but the low friction MoS_1.86 film (examined by ESMA) was understoichiometric. The oxygen content was below the detection limit of less than 5 at.%, as is shown in the Auger electron spectroscopy measurements. The tribological pin-on-disk experiments were carried out with ceramic, cemented carbide, stainless steel and with coated steel as the pin material. These experiments showed a significant effect of the chemical composition of the intermediate layer on the tribological behaviour of the multilayer film. The pin-on-disk tests were carried out under the following standard conditions: load, 5 N; feed, 0.1 m s^-1; temperature, 22°C; relative humidity 40%. The layer system Cr₃Si/MoS₂ showed the best values, with the disk undergoing 5000 rev and the pin covering a sliding distance of 9 m. These values decreased with increasing silicon content in the intermediate layer. Thinner films yielded the same relationships with smaller absolute values. The friction coefficients μ are independent of the film thickness: 0.05 for MoS₂, 0.07 for CrSi₂/MoS₂, 0.09 for CrSi/MoS₂ and 0.1 for Cr₃Si/MoS₂.     

Fabrication of anatase-type TiO2 films by reactive pulsed laser deposition for photocatalyst application

TiO₂ films having anatase crystal structure were prepared on glass substrates by reactive pulsed laser deposition using a metallic Ti target in an O₂ gas ambient. At a fixed substrate temperature of 400 °C, the crystalline structure, surface morphology, optical properties and photocatalytic activity of the TiO₂ films were greatly affected by the O₂ gas pressure. It was found that nearly pure anatase-phase TiO₂ film can be obtained under an O₂ pressure of 15 Pa, which had smallest grain size among the films deposited under various O₂ gas pressure from 5 to 30 Pa. This film also showed good optical transmittance between the wavelength of 200 and 800 nm and high photocatalytic efficiency on the decomposition of methylene blue in aqueous solution. Discussions were given to explain the experimental phenomena.     

Charge trapping and ac-electrical conduction in nanocrystalline erbium manganate film on Si substrate

Thin film of nanocrystalline ErMnO₃ was prepared by thermal annealing of Er–Mn oxide film deposited on p-Si(1 0 0) substrates. The X-ray fluorescence (XRF) and X-ray diffraction (XRD) technique were used to investigate the structure of the prepared Er–Mn oxide films. XRD study shows that films pre-annealed at 400 °C have amorphous structure and they were crystallised forming ErMnO₃ compound under pre-annealing at 800 °C or more. Moreover, in the prepared Er–Mn oxide films, Er oxide or Mn oxide cannot be crystallised each alone, but instead they interact chemically with each other forming ErMnO₃ compound. A comprehensive study on electrical properties was carried on. The ac-conductance and capacitance as a function of gate voltage, frequency, and temperature were studied on samples made in form of metal/oxide film/Si MOS devices. The fixed charge and interface state densities were determined and their variation with annealing process was studied and explained. It was found that the “correlated barrier hopping” CBH model controls the frequency dependence of the ac-conductivity, while Kramers–Kronig (KK) relations explain the frequency dependence of the relative permittivity. The parameters of CBH model were determined showing that the ac-conduction is realised by bipolaron hopping mechanism. dc conduction properties were also studied through the voltage and temperature dependence of the leakage dc-current density. The obtained dc-data follow a space charge limited current (SCLC) mechanism.     

On the extrusion of silver-sheathed superconducting billets fabricated by explosive compaction of YBa2Cu3O7 powder

Explosive compaction of YBa₂Cu₃O₇ superconducting powder and forward extrusion of the produced “green” billet were employed to fabricate high critical temperature, T_c, superconducting composite rods consisting of a superconducting YBa₂Cu₃O₇ core and a silver metallic sheath. Experimental observations regarding the “soundness” of the fabricated component with respect to the compacting and processing conditions used as well as to the properties of the superconducting powder are reported. Microstructural and stochiometric changes and defects occuring in the “green” compacted billet and the extruded rod are indicated and discussed.     

Microstructure, mechanical and electrochemical properties evaluation of pulsed DC reactive magnetron sputtered nanostructured Cr-Zr-N and Cr-Zr-Si-N thin films

Cr-Zr-Si-N thin films with various Zr contents were deposited by a bipolar asymmetric pulsed DC reactive magnetron sputtering system. In addition, a Cr-Zr-N film without Si addition was fabricated as a reference. The influence of Zr on the constitution, microstructure, mechanical, tribological and electrochemical properties of Cr-Zr-Si-N films was investigated. The microstructure of thin films was determined by a glancing angle X-ray diffractometer (GA-XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. A nanoindenter, a Vickers micro hardness tester and pin-on-disk wear tests were adopted to evaluate the hardness, toughness and tribological properties of thin films, respectively. The electrochemical properties of thin films were also evaluated in 3.5 wt.% NaCl aqueous solution. In case of the Cr-Zr-Si-N films, the Si content was fixed around 6-8 at.% and various Zr contents ranging from 0.5 to 13.6 at.% were achieved by changing the Zr target power density. In comparison to the Cr-Zr-N reference film, the addition of ~ 7.0 at.% Si in Cr-Zr-Si-N films resulted in a refined columnar structure and enhanced mechanical and anti-corrosion properties. A lattice constant expansion of these films was observed with increasing Zr content. A nanostructured thin film with around 5-10 nm grain size was obtained in case of a Cr-13.6 at.% Zr-6.8 at.% Si-N film. In general, the hardness, plastic deformation resistance and corrosion resistance increased also with increasing Zr content in the Cr-Zr-Si-N films. The Cr-Zr-Si-N film containing 13.6 at.% Zr exhibited a combination of high hardness, good mechanical properties, adequate tribological performance and excellent corrosion resistance in this study.     

Tarnishing resistance of silver–palladium thin films

Ag–Pd decorative coatings are supposed to provide better tarnishing resistance as compared to pure Ag, while keeping good optical (brightness) and mechanical properties (ductility). Palladium has a similar optical appearance as silver, and forms a thin protective oxide surface layer. Thus, a small incorporation of Pd in Ag could improve its tarnishing resistance.

Thin Ag–Pd films were deposited by magnetron co-sputtering from Pd and Ag targets. The Ar gas pressure, target power and substrate temperature were varied to modify the chemical composition of the films and optimise their properties.

The optical properties of the films were evaluated by spectroscopic ellipsometry and colorimetry. Increasing Ar gas pressure and substrate temperature results in a drastic decrease of the specular reflectivity of the films. At constant deposition conditions the reflectivity of the Ag–Pd films decreases with increasing Pd content.

The film hardness, evaluated by nanoindentation, increases with Pd content.

The tarnishing resistance of the films was evaluated by sulphidation tests. The colour change of the films due to the sulphidation was measured by colorimetry. The nature of chemical bonds of the tarnished products was evidenced by XPS. The results suggest an improvement of tarnishing resistance of the Ag–Pd films with increasing Pd content.     

光电化学响应分析Ni201在中性溶液中形成表面钝化膜的半导体性质

应用光电化学响应法和:Mott-Schottky曲线法,研究了Ni201在500℃空气中生成的氧化膜和在pH值为8.4的中性缓冲溶液中阳极氧化生成钝化膜的半导体性质,分析了Ni201表面钝化膜的结构和组成.Mott-Schottky曲线表明,Ni20l在该中性溶液中生成钝化膜的平带电位约为0.40 V,其在500℃空气中生成的氧化膜的平带电位约为0.15 V,前者的载流子浓度约是后者的34倍.在中性缓冲溶液中生成钝化膜的光电流谱表明,Ni201的结构由内层NiO和外层Ni（OH）₂构成,其带隙宽度分别为2.8和1.6 eV.其中,具有晶体结构的内层NiO的带隙宽度与Ni201在500℃空气中生成的氧化膜的带隙宽度2.4 eV相似.通过光电化学法和Mott-Schottky曲线建立Ni201表面钝化膜的电子能带结构模型,解释了其内层NiO和外层Ni（OH）₂同是p型半导体组成的钝化膜的半导体性质.     

Investigation of nitrogen mass transfer within an industrial plasma nitriding system I: The role of surface deposits

It has been proposed that in plasma nitriding, sputtering of material from biased components within the chamber assists in the nitrogen mass transfer process. Here, we investigate the effects of this sputter deposition process on the nitriding response of biased and unbiased AISI P20 steel samples mounted in a large-scale plasma nitriding system operated at 520 °C. Films with nanostructured morphologies resulting from Volmer-Weber film growth were observed on Si substrates placed adjacent to AISI P20 steel substrates after nitriding experiments. Auger depth profiling revealed that the films on the Si substrates had a stoichiometric ratio of 4:1 Fe:N. This suggested that the particles consisted largely of Fe₄N and it was concluded that they were formed from atoms and small clusters sputtered from biased components in the chamber. Despite the deposition of these films, no significant improvement in surface hardness was observed in the steel samples unless bias was applied to them. Furthermore, the maximum hardness achieved in biased P20 samples after the nitriding process occurred in the samples positioned adjacent to the Si samples supporting the thinnest deposited films. These findings do not support the proposition that in plasma nitriding, nitrogen mass transfer occurs predominantly by sputter deposition of iron nitride.     

Intermittent metal cutting at small cutting depths—2. Cutting forces

Cutting forces in intermittent metal cutting at small cutting depths were investigated by single edge experiments. Single cutting strokes were performed in a modified Charpy pendulum tester which offers cutting and thrust force measurement and accurate selection of cutting speed and feed in ranges typical for many intermittent high speed steel (HSS) tool operations.

The cutting performance of a number of double rake HSS edges, with primary rake angles ranging from +20° (“parrot bill”) to −60°, all with a preground 0.1 mm flank length were tested in two steel grades (one plain carbon and one austenitic stainless). Some of the edge geometries were tested also in TiN coated condition. The relative performance of the different edges was investigated with respect to specific cutting and thrust forces. The influence of cutting length and depth, edge micro geometry, TiN coating and cutting speed is discussed specifically.

Among the most important observations were:

• The cutting and thrust forces at a fixed cutting depth may change significantly during the short (25–30 mm) cuts.

• The chamfer formed by a double rake geometry with negative primary angle increases the forces.

• For these chamfered tools the forces increase linearly with the projected flank length. TiN coating increases rather than reduces the forces during these short cuts.

The relationships between the varied parameters and chip formation phenomena like dead zone formation, chip curl and surface finish were presented in part 1 of this paper.     

Microstructure and Properties of WB2/Cr Multilayer Films with Different Bilayer Numbers Deposited by Magnetron Sputtering

The influence of the bilayer number on the microstructure, mechanical properties, adhesion strength and tribological behaviors of the WB₂/Cr multilayer films was systematically investigated in the present study. Five groups of WB₂/Cr films with the same modulation ratio were synthesized by magnetron sputtering technique. The crystalline structure of the films was determined by X-ray diffraction. The morphologies and the microstructure of the films were observed by scanning electron microscopy, atomic force microscopy and transmission electron microscopy. Furthermore, Nano indenter, scratch tester and ball-on-disc tribometer were used to evaluate the mechanical and tribological properties. As bilayer numbers varied from 5 to 40, the hardness increased first and then decreased with the maximum hardness of 33.9 GPa when the bilayer number is 30. The H/E^* and H³/E^*2 values calculated to evaluate the fracture toughness showed the similar changing trend with hardness. The adhesion strength reached the maximum of 67 N when the bilayer number is 30. The surface roughness and friction coefficient decreased with increasing bilayer number. The wear mechanism was also investigated, and the results suggested that the multilayer film with bilayer number of 30 exhibited the best wear resistance (1.78 × 10^-7 mm³/Nm), benefiting from the contribution of high hardness, fracture toughness and adhesion strength.     

Characteristics of arc plasma deposited TiAlZrCN coatings

TiAlZrCN superhard coatings, in which Ti and Al were additions to ZrCN base compound, were prepared by the cathodic arc method. The films were deposited on Si, plain carbon steel and high-speed steel substrates in a mixture of N₂ and CH₄ gases. Elemental and phase composition, chemical bondings, texture, surface roughness, hardness, adhesion, tribological characteristics and erosive–corrosive resistance were investigates as a function of gas composition and total gas flow rate, using XPS, GDOES and XRD techniques, surface profilometry, microhardness and scratch adhesion measurements, tribological and erosive tests. It was shown that the properties and performance of the coatings were strongly dependent on the CH₄/(CH₄ + N₂) flow rate and also on the total gas flow. The tribological and anti-erosive characteristics of the TiAlZrCN coatings were found to be superior to those of reference films (ZrN, ZrC, ZrCN, and TiAlCN). Maximum hardness values (42–45 GPa) were obtained for the films prepared at CH₄/(CH₄ + N₂) ratios ranging from 0.2 to 0.4.     

Microstructure and mechanical properties of Cr–Si–N coatings prepared by pulsed reactive dual magnetron sputtering

Cr–Si–N thin films were deposited by pulsed DC reactive dual-magnetron sputtering using Cr and Si targets, while various currents applied to the Si target allowed one to vary the Si content (C_Si) in the films. Microstructure, composition and mechanical properties were studied as a function of C_Si using XRD, ERD-TOF and depth-sensing indentation. Three regions of C_Si were distinguished: (i) C_Si < 2.3 at.%, where the grain size (D) does not significantly change with increasing C_Si; (ii) 2.3 < C_Si < 6.7 at.%, where D decreases as C_Si increases; and (iii) 6.7 ≤ C_Si ≤ 11.6 at.%, where a relatively rapid decrease of D is observed with increasing C_Si. We found that the hardness (H) and the reduced Young's modulus (E_r) of the films reached maximum values of H ~ 24 GPa and E_r ~ 240 GPa for C_Si ~ 2.3 at.%. Based on the evolution of the microstructural and mechanical properties of the Cr–Si–N films, we propose to explain the hardening observed for C_Si < 2.3 at.% in terms of the solid solution mechanism rather than the nanocomposite formation.