The Characterization of Sputtered Zr-Ge-N Thin Films as Diffusion Barriers Between Copper and Silicon

The main purpose of the present micro-structural analysis by transmission electron microscopy(TEM)and X-ray diffraction(XRD)was to investigate whether amorphous Zr-Ge-N films are a potential candidate as a diffusion barrier for Cu wiring used in Si devices.The Zr-Ge-N films were prepared by a radio frequency(RF)reactive magnetron sputter-deposition technique using N2 and Ar mixed gas,and the film structure was found to be sensitive to the gas flow ratio of N2 vs.Ar during sputtering.Polycrystalline Zr-Ge-N films were obtained when the N2/(Ar+N2)ratio was smaller than 0.2 and amorphous-like Zr-Ge-N films were obtained when the ratio was larger than 0.3.Diffusion barrier test was performed by annealing the Cu/Zr-Ge-N/Si film stack under Ar atmosphere.The deposited Zr-Ge-N(C)films remained amorphous even after high temperature annealing.The Cu diffusion profile in the film was assessed by the Auger electron spectroscopy(AES).The results indicate that Cu diffusion was minimal in amorphous Zr-Ge-N(C)films even at high annealing temperatures of 800℃.     

Low-temperature growth of stoichiometric aluminum nitride films prepared by magnetic-filtered cathodic arc ion plating

AlN films were prepared on Si(100) and quartz glass substrates with high deposition rate of 30 nm·min~(-1) at the temperature of below 85℃ by the magnetic-filtered cathodic arc ion plating(FCAIP) method. The as-deposited AlN films show very smooth surface and almost no macrodroplets. The films are in amorphous state, and the formation of AlN is confirmed by N1s and Al2p X-ray photoelectron spectroscopy(XPS). The XPS depth profile analysis shows that oxygen is mainly absorbed on the AlN surface. The AlN film has Al and N concentrations close to the stoichiometric ratio with a small amount of Al_2O_3. The prepared AlN films are highly transparent over the wave-length range of 210–990 nm. The optical transmission spectrum reveals the bandgap of 6.1 eV. The present technique provides a good approach to prepare large-scale AlN films with controlled structure and good optical properties at low temperature.     

Synthesis and properties of Cr-Al-Si-N films deposited by hybrid coating system with high power impulse magnetron sputtering (HIPIMS) and DC pulse sputtering

The CrN and Cr-Al-Si-N films were deposited on Si wafer and SUS 304 substrates by a hybrid coating system with high power impulse magnetron sputtering (HIPIMS) and a DC pulse sputtering using Cr and AlSi targets under N2/Ar atmosphere.By varying the sputtering current of the AlSi target in the range of 0-2.5 A,both the Al and Si contents in the films increased gradually from 0 to 19.1% and 11.1% (mole fraction),respectively.The influences of the AlSi cathode DC pulse current on the microstructure,phase constituents,mechanical properties,and oxidation behaviors of the Cr-Al-Si-N films were investigated systematically.The results indicate that the as-deposited Cr-Al-Si-N films possess the typical nanocomposite structure,namely the face centered cubic (Cr,Al)N nano-crystallites are embedded in the amorphous Si3N4 matrix.With increasing the Al and Si contents,the hardness of the film first increases from 20.8 GPa for the CrN film to the peak value of 29.4 GPa for the Cr0.23Al0.14Si0.07 N film,and then decreases gradually.In the meanwhile,the Cr0.23Al0.14Si0.07N film also possesses excellent high-temperature oxidation resistance that is much better than that of the CrN film at 900 or 1000 °C.     

Effects of Annealing Temperature on the Structural,Optical,and Electrical Properties of ZnO Thin Films Grown on n-Si<100>Substrates by the Sol–Gel Spin Coating Method

The effects of annealing temperature on the sol–gel-derived ZnO thin films deposited on n-Sh100 i substrates by sol–gel spin coating method have been studied in this paper.The structural,optical,and electrical properties of ZnO thin films annealed at 450,550,and 650 °C in the Ar gas atmosphere have been investigated in a systematic way.The XRD analysis shows a polycrystalline nature of the films at all three annealing temperatures.Further,the crystallite size is observed to be increased with the annealing temperature,whereas the positions of various peaks in the XRD spectra are found to be red-shifted with the temperature.The surface morphology studied through the scanning electron microscopy measurements shows a uniform distribution of ZnO nanoparticles over the entire Si substrates of enhanced grain sizes with the annealing temperature.Optical properties investigated by photoluminescence spectroscopy shows an optical band gap varying in the range of 3.28–3.15 eV as annealing temperature is increased from 450 to 650 °C,respectively.The fourpoint probe measurement shows a decrease in resistivity from 2:1 10 2to 8:1 10 4X cm with the increased temperature from 450 to 650 °C.The study could be useful for studying the sol–gel-derived ZnO thin film-based devices for various electronic,optoelectronic,and gas sensing applications.     

Growth of MgO Thin Film on Silicon Substrate by MOCVD

Highly oriented MgO(111)and MgO(100)thin films have been deposited on Si(111)and Si(100)substratesby using Low Pressure MOCVD(LPMOCVD).Magnesium 2,4-pentanedionate was used as the source ma-terial.The films have a very smooth surface morphology and optical transparency with an index of refractionof 1.71(632.8 nm).Typical growth rate of the films is 1.0 μm/h.The data of X-ray diffraction analysis indi-cate that the films are fully textured with(111)and(100)orientation perpendicular to the substrate surfacerespectively.The main parameters having influence on the deposition are the substrate temperature,the totalpressure in the reaction chamber,the reaction gases and its flowrate.     

High-temperature tribological properties of Ni-P alloy coatings deposited by electro-brush plating

High-temperature tribological properties of Ni-P alloy coatings processed by electro-brush plating on 20CrMo steel have been investigated. A ball-on-disc configuration was employed and 4 mm diameter Si3N4 balls were used as static counterpart. All the wear tests were carried out at 450°C for 180 min without lubricants. The electro-brush plating Ni-P coating is amorphous in as-deposited condition, and it becomes polycrystalline with the formation of Ni and Ni3P after heat treatment at 450°C for 1 h. The friction coefficient of the Ni-P coating is just 50% of that of the 20CrMo steel at the friction temperature of 450°C. A mild adhesive wear mechanism was found for the electro-brush plating Ni-P coating tested at 450°C, whereas for the 20CrMo steel at the same temperature a mixed adhesive and abrasive wear mechanism was observed.     

Preparation and characterization of GaN films grown on Ga-diffused Si （111） substrates

Hexagonal GaN films were prepared by nitriding Ga2O3 films with flowing ammonia. Ga2O3 films were deposited on Ga-diffused Si (111) substrates by radio frequency (r.f.) magnetron sputtering. This paper have investigated the change of structural properties of GaN films nitrided in NH3 atmosphere at the temperatures of 850, 900, and 950℃ for 15 min and nitrided at the temperature of 900℃ for 10, 15, and 20 rain, respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the structure, surface morphology and composition of synthesized samples. The results reveal that the as-grown films are polycrystalline GaN with hexagonal wurtzite structure and GaN films with the highest crystal quality can be obtained when nitrided at 900℃ for 15 min.     

Structural and physical properties of permalloy thin films prepared by DC magnetron sputtering at different substrate temperature

Permalloy Ni80Fe20 films have been grown on thermal oxidized Si (111) wafers by magnetron sputtering at well-controlled substrate temperatures of 300, 500, 640 and 780 K in 0.65 Pa argon pressure. The base pressure was about 1×10-4 Pa. The deposition rate was about 5 nm/min for all the films. The structure of the films was studied using X-ray diffraction, scanning electron microscopy and atomic force microscopy. The composition of the films was analyzed using scanning Auger microprobe. The resistance and magnetoresistance of the films were measured using four-point probe technique. The results show that the content of oxygen in the films decreases gradually with raising substrate temperature. In addition, the surface morphology of the films presents notable change with the increasing of the substrate temperature; the residual gases and defects decrease and the grains have coalesced evidently, and then the grains have grown up obviously and the texture of (111) orientation develops gradually in the grow     

STRUCTURE, MECHANICAL PROPERTIES AND THERMAL STABILITY OF DIAMOND-LIKE CARBON FILMS PREPARED BY ARC ION PLATING

Diamond-like Carbon (DLC) films have been prepared on Si(lO0) substrates by arc ion plating in conjunction with pulse bias voltage under He atmosphere. The deposited films have been characterized by scanning electron microscopy and atomic force microscopy. The results show that the surface of the film is smooth and dense without any cracks, and the surface roughness is low. The bonding characteristic of the films has been studied by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. It shows the sp^3 bond content of the film deposited at -200V is 26. 7%. The hardness and elastic modulus of the film determined by nanoindentation technique are 30.8 and 250.1GPa, respectively. The tribological characteristic of the films reveals that they have low friction coefficient and good wear-resistance. After deposition, the films have been annealed in the range of 350-700℃ for 1h in vacuum to investigate the thermal stability. Raman spectra indicate that the ID/IG ratio and G peak position have few detectable changes below 500℃. Further increasing the annealing temperature, the hydrogen can be released, the structure rearranges, and the phase transition of sp^3 configured carbon to sp^2 configured carbon appears.     

Exchange bias on polycrystalline BiFeO_3/Co_2Fe(Al_(0.5)Si_(0.5)) heterostructures

Polycrystalline antiferromagnetic BiFeO_3(BFO)thin films were grown on Si/Si O_2/Ti/Pt(111) substrates by pulsed laser deposition and then ferromagnetic films Co_2Fe(Al_(0.5)Si_(0.5))(CFAS) by magnetron sputtering. After fabrication, the films were vacuum-annealed under a 0.1-T magnetic field at different temperatures from 150 to 500 °C.The exchange bias field can be tuned by the annealing temperature for the heterostructures, and the electric domain size can be controlled by the crystal grain size. A large exchange bias of about 5*10~(-3)T is observed in one of the samples. It can be speculated that the crystal grain sizes are the key element in determining the exchange bias and coercivity of the films annealed at the temperature of higher than Neel temperature(T N) of BFO. Furthermore, it is possible to extend spin theories from single-crystal BFO system to polycrystalline BFO system.     

Preparation of Ti-based amorphous brazing alloy

A new kind of amorphous active brazing alloy foil with the composition of Ti40Zr25Ni15Cu20 was successfully synthesized using melt spinning in roll forging machine in argon atmosphere. The amorphous structure and composition were examined by X-ray diffraction, differential thermal analysis and energy dispersive X-ray detector. The results show that the Ti40Zr25Ni15Cu20 amorphous alloy foil has excellent wettability on Si3N4 ceramic and demonstrate a strong glass forming ability. The reduced glass transition temperature （Trg） and the temperature interval of supercooled liquid region before crystallization are 0.76 and 78 K, respectively.     

Ti-Si-N films prepared by magnetron sputtering

A film growth mechanism, expressed in terms of depositing hard films onto the soft substrate, was proposed. Multicomponent thin films of Ti-Si-N were deposited onto Al substrate with a double-target magnetron sputtering system in an Ar-N2 gas mixture. The Ti-Si-N films were investigated by characterization techniques such as X-ray diffraction (XRD), atomic force microscope (AFM), electron probe microanalyzer (EPMA), scratch test and nanoindentation. The as-deposited films have a good adhesion to Al substrate and appear with smooth and lustrous surface. The films show nanocomposite structure with nano TiN grains embedded in an amorphous SiNx matrix. The maximum hardness of the films was achieved as high as 27 Gpa. The influences of the N2 flow rate and substrate temperature on the growth rate and quality of the films were also discussed. For all samples, the Ar flow rate was maintained constant at 10 ml. min-1, while the flow rate of N2 was varied to analyze the structural changes related to chemical composition and friction coefficient. The low temperature in the deposited Ti-Si-N films favors the formation of crystalline TiN, and it leads to a lower hardness at low N2 flow rate. At the same time, the thin films deposited are all crystallized well and bonded firmly to Al substrate, with smooth and lustrous appearance and high hardness provided. The results indicate that magnetron sputtering is a promising method to deposit hard films onto soft substrate.     

Corrosion Behaviour of Annealed Cnx／Tiny Multilayers

The corrosion behaviour of annealed CNx/TiNy multilayers have been investigated using potentiodynamic test in a 0.5MH2SO4 solution. The coating has been deposited on W6MoSCr4V2 steel by reactive magnetron sputtering and then annealed at different temperature. The annealed multilayers showed superior corrosion resistance as compared to the as-deposited coating, The corrosion model of annealed CNx/TiNy multilayers has been set up.     

Structure and magnetic properties of amorphous and polycrystalline Fe3O4 thin films

Half-metallic Fe3O4 films prepared by-DC magnetron reactive sputtering with a tantalum（Ta） buffer layer was investigated. Primary emphasis is placed on the structural impact on its magnetic properties. The experimental results show that the amorphous Fe3O4 films exhibit a superparamagnetic response at a large-scale from 20 nm to 150 nm, and the magnetoresistance （MR） isn＇t detected. By contrast, the polycrystalline Fe3O4 films possess large saturation magnetization Ms of 420 A/（kg.cm） and a clear magnetoresistance with a field of 40 kA/m. The unusual properties for the amorphous Fe3O4 film are attributed to the existing large density of the similar structure as anti-phase boundaries in the film.     

Influence of Sputtering Power on the Structure and Electrical Properties of Bi_2Fe_4O_9 Thin Films

Bismuth ferrite(Bi_2Fe_4O_9) thin films were grown on p-type Si(100) substrate by radio-frequency magnetron sputtering at 873 K. X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy studies revealed that the grown films have single-phase polycrystalline nature and are crystallized in orthorhombic structure. The grain size of the grown thin films was found to increase(56–130 nm) with sputtering power. Atomic force microscopy images clearly illustrated that the grown thin films have smooth surface. Energy-dispersive X-ray analysis revealed the presence of Bi, Fe and O elements with desired ratio and also the absence of impurities in the grown films. Analysis of ferroelectric hysteresis loops revealed that the remanent polarization and coercive field increase with the increase in sputtering power. Vicker's hardness analysis showed that the hardness of films strongly depends on the grain size and film thickness, which are mainly determined by the sputtering power. The above observations revealed that Bi_2Fe_4O_9 thin film deposited at higher sputtering power has good crystallinity and shows better electrical properties.     

MAGNETORESISTANCE EFFECT OBSERVED IN Fe／Mo MULTILAYERS PREPARED BY ELECTRON BEAM EVAPORATION

The Fe/Mo multilayers were prepared by electron beam evaporation, the micro structure and magnetic properties of the multilayers were studied by X-ray diffraction, vibrating-sample magnetometer (VSM) et al. The experimental results revealed that the Fe/Mo multilayers in our experimental conditions behaved magnetoresistance effect with a sharp peak on magnetoresistance (MR) ratio curve, and magnetoresistance is easily saturated at low applied magnetic fields. For [Fe(1.5nm)/Mo(1.0nm)]4,2 multilayers, MR ratio could arrive to 0.1%. The antiferromagnetic interlayer coupling could be observed in some films at room temperature. The strength of the antiferromagnetic interlayer coupling J in the films is low because of the low saturation field Hs. The relationship between magnetic properties and micro structure was also discussed in this paper.     

Ferroelectric properties of dysprosium-doped Bi4Ti3O12 thin films crystallized in various atmospheres

Dysprosium-doped Bi4Ti3O12 （Bi3.4Dy0.6Ti3O12, BDT） ferroelectric thin films were deposited on Pt（111）/Ti/SiO2/Si（111） substrates by chemical solution deposition （CSD） and crystallized in nitrogen, air and oxygen atmospheres, respectively. X-ray diffraction （XRD） and scanning electron microscopy （SEM） were used to identify the crystal structure, the surface and cross-section morphology of the deposited ferroelectric films. The results show that the crystallization atmosphere has significant effect on determining the crystallization and ferroelectric properties of the BDT films. The film crystallized in nitrogen at a relatively low temperature of 650 ℃, exhibits excellent crystallinity and ferroelectricity with a remanent polarization of 2Pr = 24.9 ℃/cm^2 and a coercive field of 144.5 kV/cm. While the films annealed in air and oxygen at 650 ℃ do not show good crystallinity and ferroelectricity until they are annealed at 700 ℃. The structure evolution and ferroelectric properties of BDT thin films annealed under different temperatures （600-750 ℃） were also investigated. The crystallinity of the BDT films is improved and the average grain size increases when the annealing temperature increases from 600 ℃ to 750 ℃ at an interval of 50 ℃. However, the polarization of the films is not monotonous function of the annealing temperature.     

CARBON NITRIDE FILMS PREPARED AT DIFFERENT N2／Ar RATIOS BY CLOSED FIELD UNBALANCED REACTIVE MAGNETRON SPUTTERING

Carbon nitride ( CNx thin films have been deposited onto Si(100) (for structural and mechanical analyses) and M42 high-speed-steel (for tribological measurements) substrates at room temperature by closed-field unbalanced magnetron sputtering. The mechanical and tribological properties of these films were highly dependent on the N/C concentration ratio that was adjusted by the F(N2)/F(Ar) flow-rate ratio at fixed substrate biasing of -60V during deposition. The films were characterized by employing scanning electron microscopy (SEM), atomic force microscopy (AFM), nano-indentation measurements, X-ray photoelectron spectroscopy (XPS), Raman scattering and Fourier transform infrared (FTIR) spectroscopy, pin-on-disc tribometer, scratch tester, and Rockwell-C tester. The results showed that the N content in the films increased with the N2 pressure. However, the maximum N/C ratio obtained was 0.25. The nanohardness was measured to be in the range of 11.7-20.8 GPa depending on the N/C ratios. The XPS N 1s spectra showed the existence of both N-C sp^2 and N-C sp^3 bonds in films. Raman and FTIR spectra exhibited that N-C bonds were fewer when compared to other N-C bonds. The friction coefficient of the film deposited onto steel substrate with N/C=0.26 was measured to be -0.08 and for film with N/C=0.22 a high critical load of 70N was obtained. The tribological data also showed that the wear rates of these films were in the range of -10^-16m^3/Nm, indicating excellent wear resistance for CNx films.     

Effects of substrate temperature and annealing treatment on the microstructure and magnetic characteristics of TbDyFe films

A series of TbDyFe films were prepared by DC magnetron sputtering. The effects of substrate temperature and annealing temperature on the phase structure and the magnetic properties of the sample films were investigated. The an-nealing treatment has a significant influence on the microstructure and the magnetic properties of the sample. The results obtained by XRD indicate that the films deposited at a temperature lower than 525℃ are amorphous and have an easy magnetization direction perpendicular to the film plane. An RFe2 phase is formed in the sample annealed at 550℃ and the residual phases observed are Fe and rare earth oxide. The magnetic properties Hc and Mr/Ms of the film annealed at 550℃ obtain the maximum values,for which the formation of the RFe2 phase is mainly responsible. An annealing treatment leads to a rotation of the sample’s easy axis from being parallel to the film surface to becoming vertical.     

Improvement of epitaxy and crystallinity in YBa2Cu3Oy thin films grown on silicon with double buffer of ECO/YSZ

A novel double buffer of Eu2CuO4 （ECO）/YSZ （yttrium-stabilized zirconia） was developed for growing YBa2Cu3Oy （YBCO） thin films on Si substrates. In these films, the severe reaction between Si and YBCO is blocked by the first YSZ layer, whereas, the degradation of crystallinity and superconductivity in the grown YBCO is greatly improved by the second ECO layer. Such an ECO material possesses a very stable 214-T＇ structure and excellent compatibilities with YBCO and YSZ. The result shows that the epitaxy and crystallinity of YBCO deposited on Si could be considerably enhanced by using the ECO/YSZ double buffer. The grown films are characterized by high-resolution X-ray diffraction, grazing incidence X-ray reflection, and transmission electron microscopy （TEM）, respectively. It is found that well defined interfaces are formed at YBCO/ECO/YSZ boundaries. No immediate layer could be seen. The defect density in all grown layers is kept at a lower level. The YBCO film surface turns out to be very smooth. These films have full superconducting transitions above 88 K and high current carrying capacity at 77 K. The successful growth of highly epitaxial YBCO thin films on silicon with ECO/YSZ buffer, demonstrate the advantages of such a double buffer structure.