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1.
SiCxNy thin films with different nitrogen contents were deposited by way of incorporation of different amounts of nitrogen into SiC0.70 using unbalanced reactive dc magnetron sputtering method. Their phase configurations, nanostructures and mechanical behaviors were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and microindentation methods. The result indicated SiC0.70 and all SiCxNy thin films exhibited amorphous irrespective of the nitrogen content. The phase configuration and mechanical behaviors of SiCxNy thin films strongly depended on nitrogen content. SiC0.70 exhibited a mixture consisting of SiC, Si and a small amount of C. Incorporated nitrogen, on one hand linked to Si, forming SiNx, on the other hand produced CNx and C at the expense of SiC. As a result, an amorphous mixture consisting of SiC, SiNx, C and CNx were produced. Such effects were enhanced with increase of nitrogen content. A low hardness of about 16.5 GPa was obtained at nitrogen-free SiC0.70. Incorporation of nitrogen or increase of nitrogen content increased the film hardness. A microhardness maximum of ∼29 GPa was obtained at a nitrogen content of 15.7 at.%. This value was decreased with further increase of N content, and finally a hardness value of ∼22 GPa was obtained at a N content of ∼25 at.%. The residual compressive stress was consistent with the hardness in the nitrogen content range of 8.6-25.3 at.%.  相似文献   

2.
Hafnium oxynitride (HfOxNy) gate dielectric has been deposited on Si (1 0 0) by means of radio frequency (rf) reactive sputtering using directly a HfO2 target in N2/Ar ambient. The thermal stability and microstructural characteristics for the HfOxNy films have been investigated. XPS results confirmed that nitrogen was successfully incorporated into the HfO2 films. XRD analyses showed that the HfOxNy films remain amorphous after 800 °C annealing in N2 ambient. Meanwhile the HfOxNy films can also effectively suppress oxygen diffusion during high temperature annealing and prevent interface layer from forming between HfOxNy films and Si substrates. AFM measurements demonstrated that surface roughness of the HfOxNy films increase slightly as compared to those pure HfO2 films after post deposition annealing. By virtue of building reasonable model structure, the optical properties of the HfOxNy films have been discussed in detail.  相似文献   

3.
Two nanocomposite Ti-Cx-Ny thin films, TiC0.95N0.60 and TiC2.35N0.68, as well as one pure TiN, were deposited at 500 °C on Si(1 0 0) substrate by reactive unbalanced dc-magnetron sputtering. Oxidation experiments of these films were carried out in air at fixed temperatures in a regime of 250-600 °C with an interval of 50 °C. As-deposited and oxidized films were characterized and analyzed using X-ray diffraction (XRD), microindentation, Newton's ring methods and atomic force microscopy (AFM). It was found that the starting oxidation temperature of nanocomposite Ti-Cx-Ny thin films was 300 °C irrespective of the carbon content; however their oxidation rate strongly depended on their carbon content. Higher carbon content caused more serious oxidation. After oxidation, the film hardness value remained up to the starting oxidation temperature, followed by fast decrease with increasing heating temperature. The residual compressive stress did not show a similar trend with the hardness. Its value was first increased with increase of heating temperature, and got its maximum at the starting oxidation temperature. A decrease in residual stress was followed when heating temperature was further increased. The film surface roughness value was slightly increased with heating temperature till the starting oxidation temperature, a great decrease in surface roughness was followed with further increase of heating temperature.  相似文献   

4.
Ti-Cx-Ny thin films with different nitrogen contents were deposited by way of incorporation of different amounts of nitrogen into TiC1.02 using unbalanced reactive unbalanced dc magnetron sputtering method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) and microindentation methods were used to investigate their phase configurations, nanostructures and mechanical behaviors in order to investigate their dependences on nitrogen content. The result indicated that the nitrogen content had a significant effect on phase configuration, nanostructure and mechanical behaviors of Ti-Cx-Ny thin films. The nitrogen-free TiC1.02 films exhibited a polycrystallite with nano-grains. On one hand, incorporated nitrogen substituted C in TiC1.02, producing Ti(C,N), and subsequently linked to the substituted C, forming C-N. On the other hand, the substituted C lined to each other, forming C-C. As a result, nanocomposite thin films consisting of nanocrystalline Ti(C,N) and amorphous (C, C-N) were produced. With further incorporation of nitrogen more C was substituted, accompanying with formation of more amorphous matrices and decrease of size of nanocrystalline Ti(C,N). The trend was enhanced with further increase of nitrogen content. A microhardness maximum of ∼58 GPa was obtained in nitrogen-free TiC1.02 thin films. This value was linearly decreased with incorporation of N or increase of N content, and finally a hardness value of about 28 GPa was followed at a N content of ∼25 at.%. Both elastic modulus and residual compressive stress values exhibited similar trends.  相似文献   

5.
The remote plasma nitridation (RPN) of an HfO2 film using N2 and NH3 has been investigated comparatively. X-ray photoelectron spectroscopy and Auger electron spectroscopy analyses after post-deposition annealing (PDA) at 700 °C show that a large amount of nitrogen is present in the bulk film as well as in the interfacial layer for the HfO2 film nitrided with NH3-RPN. It is also shown that the interfacial layer formed during RPN and PDA is a nitrogen-rich Hf-silicate. The C-V characteristics of an HfOxNy gate dielectric nitrided with NH3-RPN have a smaller equivalent oxide thickness than that nitrided with N2-RPN in spite of its thicker interfacial layer.  相似文献   

6.
La-doped HfO2 gate dielectric thin films have been deposited on Si substrates using La(acac)3 and Hf(acac)4 (acac = 2,4-pentanedionate) mixing sources by low-pressure metal-organic chemical vapor deposition (MOCVD). The structure, thermal stability, and electrical properties of La-doped HfO2 films have been investigated. Inductive coupled plasma analyses confirm that the La content ranging from 1 to 5 mol% is involved in the films. The films show smaller roughness of ∼0.5 nm and improved thermal stability up to 750 °C. The La-doped HfO2 films on Pt-coated Si and fused quartz substrates have an intrinsic dielectric constant of ∼28 at 1 MHz and a band gap of 5.6 eV, respectively. X-ray photoelectron spectroscopy analyses reveal that the interfacial layer is Hf-based silicate. The reliable value of equivalent oxide thickness (EOT) around 1.2 nm has been obtained, but with a large leakage current density of 3 A/cm2 at Vg = 1V + Vfb. MOCVD-derived La-doped HfO2 is demonstrated to be a potential high-k gate dielectric film for next generation metal oxide semiconductor field effect transistor applications.  相似文献   

7.
The effects of HfOxNy on the electrical property of HfOxNy-HfO2-HfOxNy sandwich-stack (signed as SS) films were investigated. Excellent electrical performances were achieved in SS films, with a high dielectric constant of 16 and a low leakage current of ∼2 × 10−8 A/cm2 at 1 MV/cm. Schottky (SK) emission and Frenkel-Poole (PF) emission are found to be the dominant mechanisms for the current conduction behavior. After a long time stress, the flat-band voltage shift in the SS film is much smaller than that in a pure HfOxNy film indicating fewer charge traps existed in the SS film. Based on the experiments, the new SS structure is more favorable for the improvement of electrical performances than a pure HfOxNy or HfO2 structure.  相似文献   

8.
A series of TiSixNy superhard coatings with different Si contents were prepared on M42 steel substrates using two Ti and two Si targets by reactive magnetron sputtering at 500 °C. These samples were subsequently vacuum-annealed at 500, 600, 700, 800 and 900 °C, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), microindenter, Rockwell hardness tester and scratch tester were applied to investigate the microstructure, phase configuration, hardness and adhesion properties of as-deposited and annealed samples. The results indicated that there were two bonds, TiN and Si3N4, in all presently deposited TiSixNy thin films, that structure was nanocomposite of nanocrystalline (nc-) TiN embedded into amorphous Si3N4 matrices. Annealing treatment below 900 °C played a little role in microstructure and hardness of the coatings although it greatly affected those of steel substrates. The film-substrate adhesion strength was slightly increased, followed by an abrupt decrease with increasing annealing temperature. Its value got to the maximum at 600 °C. Annealing had little effect on the friction coefficient with its value varying in the range of 0.39-0.40.  相似文献   

9.
Hf1−xSixOy is an attractive candidate material for high-k dielectrics. We report in this work the deposition of ultra-thin Hf1−xSixOy films (0.1 ≤ x ≥ 0.6) on silicon substrate at 450 °C by UV-photo-induced chemical vapour deposition (UV-CVD) using 222 nm excimer lamps. Silicon(IV) and hafnium(IV) organic compounds were used as the precursors. Films from around 5 to 40 nm in thickness with refractive indices from 1.782 to 1.870 were grown. The deposition rate was found to be of 6 nm/min at a temperature of 450 °C. The physical, interfacial and electrical properties of hafnium silicate (Hf1−xSixOy) thin films were investigated by using X-ray photoelectron spectroscopy, ellipsometry, FT-IR, C-V and I-V measurements. XRD showed that they were basically amorphous, while Fourier transform infrared spectroscopy (FT-IR), clearly revealed Hf-O-Si absorption in the photo-CVD deposited Hf1−xSixOy films. Surface and interfacial properties were analysed by TEM and XPS. It is found that carbon content in the films deposited by UV-CVD is very low and it also decreases with increasing Si/(Si + Hf) ratio, as low as about 1 at.% at the Si/(Si + Hf) ratio of 60 at.%.  相似文献   

10.
Sn1−xMnxO2 (x=0.01-0.05) thin films were synthesized on quartz substrate using an inexpensive ultrasonic spray pyrolysis technique. The influence of doping concentration and substrate temperature on structural and magnetic properties of Sn1−xMnxO2 thin films was systematically investigated. X-ray diffraction (XRD) studies of these films reflect that the Mn3+ ions have substituted Sn4+ ions without changing the tetragonal rutile structure of pure SnO2. A linear increase in c-axis lattice constant has been observed with corresponding increase in Mn concentration. No impurity phase was detected in XRD patterns even after doping 5 at% of Mn. A systematic change in magnetic behavior from ferromagnetic to paramagnetic was observed with increase in substrate temperature from 500 to 700 °C for Sn1−xMnxO2 (x=0.01) films. Magnetic studies reveal room-temperature ferromagnetism (RTFM) with 3.61×10−4 emu saturation magnetization and 92 Oe coercivity in case of Sn1−xMnxO2 (x=0.01) films deposited at 500 °C. However, paramagnetic behavior was observed for the films deposited at a higher substrate temperature of 700 °C. The presence of room-temperature ferromagnetism in these films was observed to have an intrinsic origin and could be obtained by controlling the substrate temperature and Mn doping concentration.  相似文献   

11.
High-k gate dielectric HfO2 thin films have been deposited on Si(1 0 0) by using plasma oxidation of sputtered metallic Hf thin films. The optical and electrical properties in relation to postdeposition annealing temperatures are investigated by spectroscopic ellipsometry (SE) and capacitance-voltage (C-V) characteristics in detail. X-ray diffraction (XRD) measurement shows that the as-deposited HfO2 films are basically amorphous. Based on a parameterized Tauc-Lorentz dispersion mode, excellent agreement has been found between the experimental and the simulated spectra, and the optical constants of the as-deposited and annealed films related to the annealing temperature are systematically extracted. Increases in the refractive index n and extinction coefficient k, with increasing annealing temperature are observed due to the formation of more closely packed thin films and the enhancement of scattering effect in the targeted HfO2 film. Change of the complex dielectric function and reduction of optical band gap with an increase in annealing temperature are discussed. The extracted direct band gap related to the structure varies from 5.77, 5.65, and 5.56 eV for the as-deposited and annealed thin films at 700 and 800 °C, respectively. It has been found from the C-V measurement the decrease of accumulation capacitance values upon annealing, which can be contributed to the growth of the interfacial layer with lower dielectric constant upon postannealing. The flat-band voltage shifts negatively due to positive charge generated during postannealing.  相似文献   

12.
To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Nitrogen and carbon doping TiO2−xyNxCy films were obtained by heating the TiO2 gel in an ionized N2 gas and then were calcined at 500 °C. The TiO2−xyNxCy films have revealed an improvement over the TiO2 films under visible light (wavelength, 500 nm) in optical absorption and photocatalytic activity such as photodegradation of methyl orange. X-ray photoemission spectroscopy, infrared spectrum and UV-visible (UV-vis) spectroscopy were used to find the difference of two kinds of films. Nitrogen and carbon doped into substitutional sites of TiO2 has been proven to be indispensable for band-gap narrowing and photocatalytic activity.  相似文献   

13.
The Zn1−xMgxO thin films were grown on Al2O3 substrate with various O2 flow rates by plasma-assisted molecular beam epitaxy (P-MBE). The growth conditions were optimized by the characterizations of morphology, structural and optical properties. The Mg content of the Zn1−xMgxO thin film increases monotonously with decreasing the oxygen flux. X-ray diffractometer (XRD) measurements show that all the thin films are preferred (0 0 2) orientated. By transmittance and absorption measurements, it was found that the band gap of the film decreases gradually with increasing oxygen flow rate. The surface morphology dependent on the oxygen flow rate was also studied by field emission scanning electron microscopy (FE-SEM). The surface roughness became significant with increasing oxygen flow rate, and the nanostructures were formed at the larger flow rate. The relationship between the morphology and the oxygen flow rate of Zn1−xMgxO films was discussed.  相似文献   

14.
Thin films of samples of the glassy SxSe100−x system with 0 ≤ x ≤ 7.28 have been prepared by thermal evaporation technique at room temperature (300 K). X-ray investigations show that the structure of pure selenium (Se) does change seriously by the addition of small amount of sulphur S ≤7.28%. The lattice parameters were determined as a function of sulphur content. Results of differential thermal analysis (DTA) of the glassy compositions of the system SxSe100−x were discussed. The characteristic temperatures (Tg, Tc and Tm) were evaluated. Dark electrical resistivities, ρ, of SxSe100−x thin films with different thicknesses from 100 to 500 nm, were measured in the temperature range from 300 to 423 K. Two distinct linear parts with different activation energies were observed. The variation of electrical resistivity of examined compositions has been discussed as a function of the film thickness, temperature and the sulphur content. The application of Mott model for the phonon assisted hopping of small polarons gave the same two activation energies obtained from the resistivity temperature calculations.  相似文献   

15.
Thin Li1+xMn2O4−δ films were deposited on several substrate materials (stainless steel, p-doped silicon and glassy carbon) by pulsed laser deposition. To obtain the correct thin film stoichiometries, targets with a different amount of excess lithium were required (Li1.03Mn2O4 + xLi2O; x = 2.5 and 7.5 mol%). The resulting polycrystalline thin films were characterized with respect to their morphology and electrochemical activity. It was found that only thin Li1+xMn2O4−δ films deposited on stainless steel and glassy carbon showed the typical insertion and deinsertion peaks of Li+ during cycling.  相似文献   

16.
We report (FePt)Ag-C granular thin films for potential applications to ultrahigh density perpendicular recording media, that were processed by co-sputtering FePt, Ag, and C targets on MgO underlayer deposited on thermally oxidized Si substrates. (FePt)1−xAgx-yvol%C (0<x<0.2, 0<y<50) films were fabricated on oxidized silicon substrates with a 10 nm MgO interlayer at 450oC. We found that the Ag additions improved the L10 ordering and the granular structure of the FePt-C films with the perpendicular coercivity ranging from 26 to 37 kOe for the particle size of 5-8 nm. The (FePt)0.9Ag0.1-50vol%C film showed the optimal magnetic properties as well as an appropriate granular morphology for recording media, i.e., average grain size of Dav=6.1 nm with the standard deviation of 1.8 nm.  相似文献   

17.
We investigated the dc magnetic field and temperature dependences of the microwave surface resistance (Rs) of YBa2Cu3Oy (YBCO) and DyBa2Cu3Oy (DyBCO) superconducting thin films. The YBCO and DyBCO thin films, each with a thickness of 300, 500, or 700 nm, were deposited on MgO (1 0 0) substrates by the thermal co-evaporation method. The Rs was measured using the dielectric resonator method. A dc magnetic field of up to 5.0 T was applied parallel to the c-axis of the superconducting thin films. The results showed that the Rs value had almost the same temperature dependence at various thicknesses in a zero-external field. The Rs of the YBCO and DyBCO thin films increased with the applied dc magnetic field. The DyBCO thin films showed weaker magnetic field dependence of Rs than the YBCO thin films. The Rs ratio (defined as Rs(5 T)/Rs(0 T)) linearly increased with the film thickness. These results show that pinning strength decreased with an increasing film thickness.  相似文献   

18.
BiFeO3/Zn1−xMnxO (x = 0-0.08) bilayered thin films were deposited on the SrRuO3/Pt/TiO2/SiO2/Si(1 0 0) substrates by radio frequency sputtering. A highly (1 1 0) orientation was induced for BiFeO3/Zn1−xMnxO. BiFeO3/Zn1−xMnxO thin films demonstrate diode-like and resistive hysteresis behavior. A remanent polarization in the range of 2Pr ∼ 121.0-130.6 μC/cm2 was measured for BiFeO3/Zn1−xMnxO. BiFeO3/Zn1−xMnxO (x = 0.04) bilayer exhibits a highest Ms value of 15.2 emu/cm3, owing to the presence of the magnetic Zn0.96Mn0.04O layer with an enhanced Ms value.  相似文献   

19.
Herein is a report of a study on a Cd1−xZnxS thin film grown on an ITO substrate using a chemical bath deposition technique. The as-deposited films were annealed in air at 400 °C for 30 min. The composition, surface morphology and structural properties of the as-deposited and annealed Cd1−xZnxS thin films were studied using EDX, SEM and X-ray diffraction techniques. The annealed films have been observed to possess a crystalline nature with a hexagonal structure. The optical absorption spectra were recorded within the range of 350-800 nm. The band gap of the as-deposited thin films varied from 2.46 to 2.62 eV, whereas in the annealed film these varied from 2.42 to 2.59 eV. The decreased band gap of the films after annealing was due to the improved crystalline nature of the material.  相似文献   

20.
A series of ZnO1−xSx alloy films (0 ≤ x ≤ 1) were grown on quartz substrates by radio-frequency (rf) magnetron sputtering of ZnS ceramic target, using oxygen and argon as working gas. X-ray diffraction measurement shows that the ZnO1−xSx films have wurtzite structure with (0 0 2) preferential orientation in O-rich side (0 ≤ x ≤ 0.23) and zinc blende structure with (1 1 1) preferential orientation in S-rich side (0.77 ≤ x ≤ 1). However, when the S content is in the range of 0.23 < x < 0.77, the ZnO1−xSx film consists of two phases of wurtzite and zinc blende or amorphous ZnO1−xSx phase. The band gap energy of the films shows non-linear dependence on the S content, with an optical bowing parameter of about 2.9 eV. The photoluminescence (PL) measurement reveals that the PL spectrum of the wurtzite ZnO1−xSx is dominated by visible band and its PL intensity and intensity ratio of UV to visible band decrease greatly compared with undoped ZnO. All as-grown ZnO1−xSx films behave insulating, but show n-type conductivity for w-ZnO1−xSx and maintain insulating properties for β-ZnO1−xSx after annealed. Mechanisms of effects of S on optical and electrical properties of the ZnO1−xSx alloy are discussed in the present work.  相似文献   

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