Pulsed reactive sputtering is a novel process used to deposit some compound films, which are not deposited by traditional D.C. reactive sputtering easily. In this paper some experimental results about the deposition o...Pulsed reactive sputtering is a novel process used to deposit some compound films, which are not deposited by traditional D.C. reactive sputtering easily. In this paper some experimental results about the deposition of Al oxide films by pulsed reactive sputtering are presented. The hysteresis phenomenon of the sputtering voltage and deposition rate with the change of oxygen flow during sputtering process are discussed.展开更多
With advanced research for dielectrics including capacitors in DRAMs, decoupling filters in microcircuits and insulating gates in transistors, a lot of demand for the new challenging of high-k materials in semiconduct...With advanced research for dielectrics including capacitors in DRAMs, decoupling filters in microcircuits and insulating gates in transistors, a lot of demand for the new challenging of high-k materials in semiconductor industries has been emerged. This study explores and addresses the experimental approach for composite materials with one of the major concerns of high capacitance, and low leakage, as well as ease of integration technology. The characteristics of Al<sub>2</sub>O<sub>3</sub> supported HfO<sub>2</sub> (AHO) thin films for a series of different Hf ratios with Al<sub>2</sub>O<sub>3</sub> dielectrics by atomic layer deposition demonstrated as a candidate material. A composite AHO films with the homogeneous compositions of Al and Hf atoms into the Al-Hf-O mixed oxide system could stabilize the polycrystalline structure with increasing of dielectric constant (k) and decreasing of leakage current density, as well as a higher breakdown voltage than HfO<sub>2</sub> film on its own. 70 nm thick AHO thin films with different composition of Al and Hf contents were prepared by atomic layer deposition technique on titanium nitride (TiN) and silicon dioxide (SiO<sub>2</sub>) coated Si substrates. Photolithography and metal lift-off technique were used for the device fabrication of the metal-insulator-metal (MIM) capacitor structures. AHO films on TiN/SiO<sub>2</sub>/Si were measured by semiconductor analyzer and source/ measure system with probe station in the voltage range from -5 to 5 V with a frequency range from 10 kHz to 1 MHz were used to conduct capacitance-voltage (C-V) measurements with low/medium frequency range and current-voltage (I-V) measurements. It was found that Au/AHO/TiN/SiO<sub>2</sub>/Si MIM capacitors demonstrate a capacitance density of 1.5 - 4.5 fF/μm<sup>2</sup> at 10 kHz, a loss tangent of 0.02 - 0.04 at 10 kHz, dielectric constant of 11.7 - 35.5 depending on the composition and a low leakage current of 1.7 × 10<sup>-9</sup> A/cm<sup>2</sup> at 0.5 MV/cm at room temperature. The acquired experimental results could show the possibility of compositional alloy thin films that could potentially replace or open new market for high-k challenges in semiconductor technology.展开更多
The effects of the oxygen-argon ratio on electric properties of Ta2O5 film prepared by radio-frequency magnetron sputtering were investigated.The Ta2O5 partially transforms from the amorphous phase into the crystal ph...The effects of the oxygen-argon ratio on electric properties of Ta2O5 film prepared by radio-frequency magnetron sputtering were investigated.The Ta2O5 partially transforms from the amorphous phase into the crystal phase when annealing temperatures are 800℃ or higher.The lattice constant of Ta2O5 decreases with the increase of the O2/Ar ratio,which indicates that oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies during the deposition process.For the films deposited in working gas mixtures with different O2/Ar ratios and subsequently annealed at 700℃,the effective dielectric constant is increased from 14.7 to 18.4 with the increase of the O2/Ar ratio from 0 to 1.Considering the presence of an SiO2 layer between the film and the silicon substrate,the optimal dielectric constant of Ta2O5 film was estimated to be 31.Oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies,and the oxygen vacancy density and leakage current of Ta2O5 film both decrease with the increase of the O2/Ar ratio.The leakage current decreases after annealing treatment and it is minimized at 700℃.However,when the annealing temperature is 800℃ or higher,it increases slightly,which results from the partially crystallized Ta2O5 layer containing defects such as grain boundaries and vacancies.展开更多
Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) ...Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the morphology and composition of the films fabricated in the electrolytes with and without addition of Si C nanoparticles. Results show that Si C particles can be successfully incorporated into the oxide film during the anodizing process and preferentially concentrate within internal cavities and micro-cracks. The ball-on-disk sliding tests indicate that Si C-containing oxide films register much lower wear rate than the oxide films without Si C under dry sliding condition. Si C particles are likely to melt and then are oxidized by frictional heat during sliding tests. Potentiodynamic polarization behavior reveals that the anodized alloy with Si C nanoparticles results in a reduction in passive current density to about 1.54×10-8 A/cm2, which is more than two times lower than that of the Ti O2 film(3.73×10-8 A/cm2). The synthesized composite film has good anti-wear and anti-corrosion properties and the growth mechanism of nanocomposite film is also discussed.展开更多
Effects of diffusion welding process parameters on strength of welded joint based on particle reinforced aluminium matrix composite Al 2O 3p /6061Al have been studied through comparing with aluminium matrix allo...Effects of diffusion welding process parameters on strength of welded joint based on particle reinforced aluminium matrix composite Al 2O 3p /6061Al have been studied through comparing with aluminium matrix alloy. The mechanism for loss of joint strength has been analyzed. It should be pointed out that key processing parameters affecting the strength of joint was welding temperature. The high quality joint can be successfully obtained with appropriate diffusion welding parameters.展开更多
The vibrational Raman spectra have been obtained for purified solid films C_(60). Three bands were observed out of the total of 10 that were theoretically predicted. Some phenomena which may be due to photon-induced o...The vibrational Raman spectra have been obtained for purified solid films C_(60). Three bands were observed out of the total of 10 that were theoretically predicted. Some phenomena which may be due to photon-induced oxidation in the vibrational Raman measuring were observed.展开更多
Anodizing of aluminium is widely applied when a controllable morphology and properties of the surface are required. Anodic oxide films may be developed by appropriate selection of electrolyte and film-forming conditio...Anodizing of aluminium is widely applied when a controllable morphology and properties of the surface are required. Anodic oxide films may be developed by appropriate selection of electrolyte and film-forming conditions for various applications in the fields of architecture, aerospace, electronics, packaging and printing. In the present study, the printability of aluminium with respect to anodizing conditions is discussed. In particular, AA1050 alloy specimens were anodized in either sulfuric acid or phosphoric acid at temperatures ranging from 10?C to 40?C, thereby affecting the porosity and anodic layer thickness. Both the porosity and oxide thickness increase with the temperature, whereas anodization in phosphoric acid produces thinner and more porous layer than that in sulfuric acid. After the anodization step, two different printing techniques were used (i.e. digital printing and screen printing). Printed specimens were characterized by means of colour parameters, microscopy, adhesion and light fastness test. Colour parameters and ink adhesion measurements indicate that both digital and screen printing techniques give a better print quality when the anodization step is conducted in the range of 20?C - 30?C.展开更多
文摘Pulsed reactive sputtering is a novel process used to deposit some compound films, which are not deposited by traditional D.C. reactive sputtering easily. In this paper some experimental results about the deposition of Al oxide films by pulsed reactive sputtering are presented. The hysteresis phenomenon of the sputtering voltage and deposition rate with the change of oxygen flow during sputtering process are discussed.
文摘With advanced research for dielectrics including capacitors in DRAMs, decoupling filters in microcircuits and insulating gates in transistors, a lot of demand for the new challenging of high-k materials in semiconductor industries has been emerged. This study explores and addresses the experimental approach for composite materials with one of the major concerns of high capacitance, and low leakage, as well as ease of integration technology. The characteristics of Al<sub>2</sub>O<sub>3</sub> supported HfO<sub>2</sub> (AHO) thin films for a series of different Hf ratios with Al<sub>2</sub>O<sub>3</sub> dielectrics by atomic layer deposition demonstrated as a candidate material. A composite AHO films with the homogeneous compositions of Al and Hf atoms into the Al-Hf-O mixed oxide system could stabilize the polycrystalline structure with increasing of dielectric constant (k) and decreasing of leakage current density, as well as a higher breakdown voltage than HfO<sub>2</sub> film on its own. 70 nm thick AHO thin films with different composition of Al and Hf contents were prepared by atomic layer deposition technique on titanium nitride (TiN) and silicon dioxide (SiO<sub>2</sub>) coated Si substrates. Photolithography and metal lift-off technique were used for the device fabrication of the metal-insulator-metal (MIM) capacitor structures. AHO films on TiN/SiO<sub>2</sub>/Si were measured by semiconductor analyzer and source/ measure system with probe station in the voltage range from -5 to 5 V with a frequency range from 10 kHz to 1 MHz were used to conduct capacitance-voltage (C-V) measurements with low/medium frequency range and current-voltage (I-V) measurements. It was found that Au/AHO/TiN/SiO<sub>2</sub>/Si MIM capacitors demonstrate a capacitance density of 1.5 - 4.5 fF/μm<sup>2</sup> at 10 kHz, a loss tangent of 0.02 - 0.04 at 10 kHz, dielectric constant of 11.7 - 35.5 depending on the composition and a low leakage current of 1.7 × 10<sup>-9</sup> A/cm<sup>2</sup> at 0.5 MV/cm at room temperature. The acquired experimental results could show the possibility of compositional alloy thin films that could potentially replace or open new market for high-k challenges in semiconductor technology.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61076055)the Program for Innovative Research Teams in Zhejiang Normal Universitythe Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University (Grant No. FDS KL2011_04)
文摘The effects of the oxygen-argon ratio on electric properties of Ta2O5 film prepared by radio-frequency magnetron sputtering were investigated.The Ta2O5 partially transforms from the amorphous phase into the crystal phase when annealing temperatures are 800℃ or higher.The lattice constant of Ta2O5 decreases with the increase of the O2/Ar ratio,which indicates that oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies during the deposition process.For the films deposited in working gas mixtures with different O2/Ar ratios and subsequently annealed at 700℃,the effective dielectric constant is increased from 14.7 to 18.4 with the increase of the O2/Ar ratio from 0 to 1.Considering the presence of an SiO2 layer between the film and the silicon substrate,the optimal dielectric constant of Ta2O5 film was estimated to be 31.Oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies,and the oxygen vacancy density and leakage current of Ta2O5 film both decrease with the increase of the O2/Ar ratio.The leakage current decreases after annealing treatment and it is minimized at 700℃.However,when the annealing temperature is 800℃ or higher,it increases slightly,which results from the partially crystallized Ta2O5 layer containing defects such as grain boundaries and vacancies.
基金Project(51271012)supported by the National Natural Science Foundation of China
文摘Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the morphology and composition of the films fabricated in the electrolytes with and without addition of Si C nanoparticles. Results show that Si C particles can be successfully incorporated into the oxide film during the anodizing process and preferentially concentrate within internal cavities and micro-cracks. The ball-on-disk sliding tests indicate that Si C-containing oxide films register much lower wear rate than the oxide films without Si C under dry sliding condition. Si C particles are likely to melt and then are oxidized by frictional heat during sliding tests. Potentiodynamic polarization behavior reveals that the anodized alloy with Si C nanoparticles results in a reduction in passive current density to about 1.54×10-8 A/cm2, which is more than two times lower than that of the Ti O2 film(3.73×10-8 A/cm2). The synthesized composite film has good anti-wear and anti-corrosion properties and the growth mechanism of nanocomposite film is also discussed.
文摘Effects of diffusion welding process parameters on strength of welded joint based on particle reinforced aluminium matrix composite Al 2O 3p /6061Al have been studied through comparing with aluminium matrix alloy. The mechanism for loss of joint strength has been analyzed. It should be pointed out that key processing parameters affecting the strength of joint was welding temperature. The high quality joint can be successfully obtained with appropriate diffusion welding parameters.
文摘The vibrational Raman spectra have been obtained for purified solid films C_(60). Three bands were observed out of the total of 10 that were theoretically predicted. Some phenomena which may be due to photon-induced oxidation in the vibrational Raman measuring were observed.
文摘Anodizing of aluminium is widely applied when a controllable morphology and properties of the surface are required. Anodic oxide films may be developed by appropriate selection of electrolyte and film-forming conditions for various applications in the fields of architecture, aerospace, electronics, packaging and printing. In the present study, the printability of aluminium with respect to anodizing conditions is discussed. In particular, AA1050 alloy specimens were anodized in either sulfuric acid or phosphoric acid at temperatures ranging from 10?C to 40?C, thereby affecting the porosity and anodic layer thickness. Both the porosity and oxide thickness increase with the temperature, whereas anodization in phosphoric acid produces thinner and more porous layer than that in sulfuric acid. After the anodization step, two different printing techniques were used (i.e. digital printing and screen printing). Printed specimens were characterized by means of colour parameters, microscopy, adhesion and light fastness test. Colour parameters and ink adhesion measurements indicate that both digital and screen printing techniques give a better print quality when the anodization step is conducted in the range of 20?C - 30?C.
