本文将薄膜式微谐振压力传感器谐振子简化为对边简支对边自由机电耦合微薄膜谐振系统,给出了考虑分子力作用时微薄膜压力敏感元件机电耦合系统动力学方程,推导其振型方程及频率方程,研究了分子力对系统固有频率及自由振动的影响规律.结...本文将薄膜式微谐振压力传感器谐振子简化为对边简支对边自由机电耦合微薄膜谐振系统,给出了考虑分子力作用时微薄膜压力敏感元件机电耦合系统动力学方程,推导其振型方程及频率方程,研究了分子力对系统固有频率及自由振动的影响规律.结果表明:分子力对于机电耦合微薄膜的自由振动固有频率具有重要的影响.随着系统初始间隙的减小、工作电压的增大、微薄膜厚度的减小以及薄膜长度的增大,分子力对系统固有频率的影响更加显著.在低阶模态下,分子力对固有频率的影响变大,应该予以考虑.当初始间隙减小到0.1μm时,Casimir力对固有频率的影响比van der Waals力明显,必须考虑Casimir力的影响.论文有助于薄膜式微谐振压力传感器谐振子的动力学理论分析,研究结果对于MEMS压力传感器进一步小型化具有指导意义.展开更多
O484.1 2000064012掺杂C<sub>60</sub>薄膜的制备及光电特性=Preparation andelectrical and optical properties of doped C<sub>60</sub>thin films[刊,中]/邹云娟,宋雪梅,王波,陈光华,严辉（北京工业大学应...O484.1 2000064012掺杂C<sub>60</sub>薄膜的制备及光电特性=Preparation andelectrical and optical properties of doped C<sub>60</sub>thin films[刊,中]/邹云娟,宋雪梅,王波,陈光华,严辉（北京工业大学应用物理系.北京（100022））//人工晶体学报.—1999,28（4）.—359-363在电弧法制备的过程中添加氮气或B<sub>2</sub>O<sub>3</sub>粉末,制备了氮、硼替位式掺杂C<sub>60</sub>。硼掺杂和氮掺杂C<sub>60</sub>展开更多
To decrease the size effects of friction in microforming, three kinds of surface coatings, such as diamond-like carbon（DLC）, TiN and MoS2, were deposited on surfaces of dies with plasma based ion implantation and de...To decrease the size effects of friction in microforming, three kinds of surface coatings, such as diamond-like carbon（DLC）, TiN and MoS2, were deposited on surfaces of dies with plasma based ion implantation and deposition（PBII D） method and magnetron sputtering technique, respectively. The tribological behavior of surface coatings was analyzed considering plastic deformation of specimen at contact interface. The analyses indicate that there is a lower coefficient of friction（COF） and a high wear resistance under the condition of large strain/stress when using the DLC film. The graphitization of DLC film occurs after 100 times of tests. The mechanism of graphitization was analyzed considering energy induced by friction work. The effects of DLC film properties on qualities of micro-deep drawn parts were investigated by analyzing the reduction of wall thickness, etc. The results indicate that DLC film is very helpful for improving the qualities of the micro-parts.展开更多
Al-doped ZnO thin films were prepared on glass substrate using an ultra-high density target by RF magnetron sputtering at room temperature. The microstructure, surface morphology, optical and electrical properties of ...Al-doped ZnO thin films were prepared on glass substrate using an ultra-high density target by RF magnetron sputtering at room temperature. The microstructure, surface morphology, optical and electrical properties of AZO thin films were investigated by X-ray diffractometer, scanning electron microscope, UV-visible spectrophotometer, four-point probe method, and Hall-effect measurement system. The results showed that all the films obtained were polycrystalline with a hexagonal structure and average optical transmittance of AZO thin films was over 85 % at different sputtering powers. The sputtering power had a great effect on optoelectronic properties of the AZO thin films, especially on the resistivity. The lowest resistivity of 4.5×10^-4 Ω·cm combined with the transmittance of 87.1% was obtained at sputtering power of 200 W. The optical band gap varied between 3.48 and 3.68 eV.展开更多
Large scale homogenous growth of microcrystalline silicon （μ.c-Si：H） on cheap substrates by inductively coupled plasma （ICP） of Ar diluted Sill4 has been studied. From XRD and Raman spectrum, we find that substr...Large scale homogenous growth of microcrystalline silicon （μ.c-Si：H） on cheap substrates by inductively coupled plasma （ICP） of Ar diluted Sill4 has been studied. From XRD and Raman spectrum, we find that substrates can greatly affect the crystalline orientation, and the μc-Si：H films are comprised of small particles. Thickness detection by surface profilometry shows that the thin μc-Si：H films are homogenous in large scale. Distributions of both ion density and electron temperature are found to be uniform in the vicinity of substrate by means of diagnosis of Langmuir probe. Based on these experimental results, it can be proposed that rough surfaces play important roles in the crystalline network formation and Ar can affect the reaction process and improve the characteristics of μc-Si：H films. Also, ICP reactor can deposit the thin film in large scale.展开更多
Copper （Cu） doped beryllium （Be） thin films were deposited on silicon substrates by using a simple ion beam sputtering method, which can also realize the varying of Cu doping concentration. Detailed morphological ...Copper （Cu） doped beryllium （Be） thin films were deposited on silicon substrates by using a simple ion beam sputtering method, which can also realize the varying of Cu doping concentration. Detailed morphological and structural characterizations of the samples clearly disclose a microstructure evolution of films upon doping Cu. Doping Cu can effectively suppress film grain growth, causing a small grain size as well as uniform size distribution. Furthermore, doping Cu affects the crystallographic texture of film, which leads to the formation of more compact film structure. In particular, the surface smoothness of the doped films is significantly improved, which makes them promising candidates for various applications.展开更多
Using H 2 diluted silane,series of μc Si∶H films are fabricated at low temperature with VHF PECVD.The thickness measurements reveal that the deposition rates are obviously enhanced with higher plasma excitation ...Using H 2 diluted silane,series of μc Si∶H films are fabricated at low temperature with VHF PECVD.The thickness measurements reveal that the deposition rates are obviously enhanced with higher plasma excitation frequency or working pressure,but increase firstly and then decrease with the increase of plasma power density.Raman spectra show that the crystallinity and the average grain sizes of the films strongly depend on the temperature of substrate and the concentration of silane.However,the plasma excitation frequency only has effect on the crystallinity,and a maximum occurs during the further increase of plasma excitation frequency.From XRD and TEM experiments,three preferential crystalline orientations (111),(220) and (311) are observed,and the average grain sizes are different for every crystalline orientation.展开更多
Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any pr...Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any property separately with the thickness of film, the interaction between particles of different types, the repulsion between particle and boundary, except for the dependence of the variations of mean-square bond length on the thickness of film, which exhibits as a wave trend. What＇s more, the varying trends of mean-square bond length and root-mean-square end-to-end distance can correspond to each other. The density distribution of either component in diblock copolymer film can be controlled and adjusted effectively through its interaction with boundary.展开更多
Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the ...Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n（Zn）/n（Ti） on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n（Zn）/n（Ti） typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n（Zn）/n（Ti） leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n（Zn）/n（Ti） of 1/9.3, respectively. The n（Zn）/n（Ti） shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n（Zn）/n（Ti） has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n（Zn）/n（Ti）, the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n（Zn）/n（Ti） but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n（Zn）/n（Ti）=1：9.3.展开更多
Tantalum nitride （TAN） and nichrome （NiCr） are the two most common materials used as thin film resistors （TFR） for monolithic microwave integrated circuits （MMIC） based on AlGaN/GaN high electron mobility tran...Tantalum nitride （TAN） and nichrome （NiCr） are the two most common materials used as thin film resistors （TFR） for monolithic microwave integrated circuits （MMIC） based on AlGaN/GaN high electron mobility transistors （HEMTs）. In this study,we compare the reliability of the two materials used as TFRs on a semi-insulation 4H SiC substrate. Through the comparison between NiCr and TaN thin-film resistor materials, we find the square resistor （Rs） of TaN TFR increases as the annealing temperature increases. However, the R s of NiCr TFR shows the opposite trend. We also find the change of the TaN Rs and contacted resistor （Re） is smaller than the NiCr. After O2 plasma exposure in RIE,the TaN R s only decreases 0.7Ω,or about 2.56%, and R c increases 0.1Ω,or about 6.6%, at an annealing temperature of 400℃. In contrast, the NiCr R s and R c show large changes at different annealing temperatures after O2 plasma exposure. In conclusion,TaN is more stable during plasma exposure after 400℃ annealing in N2 ambient.展开更多
A novel capacitive microwave MEMS switch with a silicon/metal/dielectric as a membrane is fabricated successfully by bonding and etching-stop process. Its principal, design, and fabricating process are described in de...A novel capacitive microwave MEMS switch with a silicon/metal/dielectric as a membrane is fabricated successfully by bonding and etching-stop process. Its principal, design, and fabricating process are described in detail. A patterned dielectric layer, Ta2O5, with dielectric constant of 24 is reached. Experiment results show this novel structure,where the switch＇s dielectric layer is not prepared on the transmission line, features very low insertion loss. The insertion loss is 0.06dB at 2GHz and lower than 0.5dB in the wider range from De up to 20GHz,especially when the transmission line metal is only 0. 5μm thick.展开更多
Vanadium carbide/titanium carbide （VC/TiC） superlattice films were synthesized by magnetron sputtering method. The effects of modulation period on the microstructure evolution and mechanical properties were investig...Vanadium carbide/titanium carbide （VC/TiC） superlattice films were synthesized by magnetron sputtering method. The effects of modulation period on the microstructure evolution and mechanical properties were investigated by EDXA, XRD, HRTEM and nano-indentation. The results reveal that the VC/TiC superlattice films form an epitaxial structure when their modulation period is less than a critical value, accompanied with a remarkable increase in hardness. Further increasing the modulation period, the hardness of superlattices decreases slowly to the rule-of-mixture value due to the destruction of epitaxial structures. The XRD results reveal that three-directional strains are generated in superlattices when the epitaxial structure is formed, which may change the modulus of constituent layers. This may explain the remarkable hardness enhancement of VC/TiC superlattices.展开更多
文摘本文将薄膜式微谐振压力传感器谐振子简化为对边简支对边自由机电耦合微薄膜谐振系统,给出了考虑分子力作用时微薄膜压力敏感元件机电耦合系统动力学方程,推导其振型方程及频率方程,研究了分子力对系统固有频率及自由振动的影响规律.结果表明:分子力对于机电耦合微薄膜的自由振动固有频率具有重要的影响.随着系统初始间隙的减小、工作电压的增大、微薄膜厚度的减小以及薄膜长度的增大,分子力对系统固有频率的影响更加显著.在低阶模态下,分子力对固有频率的影响变大,应该予以考虑.当初始间隙减小到0.1μm时,Casimir力对固有频率的影响比van der Waals力明显,必须考虑Casimir力的影响.论文有助于薄膜式微谐振压力传感器谐振子的动力学理论分析,研究结果对于MEMS压力传感器进一步小型化具有指导意义.
文摘O484.1 2000064012掺杂C<sub>60</sub>薄膜的制备及光电特性=Preparation andelectrical and optical properties of doped C<sub>60</sub>thin films[刊,中]/邹云娟,宋雪梅,王波,陈光华,严辉（北京工业大学应用物理系.北京（100022））//人工晶体学报.—1999,28（4）.—359-363在电弧法制备的过程中添加氮气或B<sub>2</sub>O<sub>3</sub>粉末,制备了氮、硼替位式掺杂C<sub>60</sub>。硼掺杂和氮掺杂C<sub>60</sub>
基金supported by the Natio-nal Natural Science Foundation of China(No.51105267)the National Research Foundation for the DoctoralProgram of Higher Education of China(No.20111402120007)~~
基金Projects(51375113,50805035)supported by the National Natural Science Foundation of China
文摘To decrease the size effects of friction in microforming, three kinds of surface coatings, such as diamond-like carbon（DLC）, TiN and MoS2, were deposited on surfaces of dies with plasma based ion implantation and deposition（PBII D） method and magnetron sputtering technique, respectively. The tribological behavior of surface coatings was analyzed considering plastic deformation of specimen at contact interface. The analyses indicate that there is a lower coefficient of friction（COF） and a high wear resistance under the condition of large strain/stress when using the DLC film. The graphitization of DLC film occurs after 100 times of tests. The mechanism of graphitization was analyzed considering energy induced by friction work. The effects of DLC film properties on qualities of micro-deep drawn parts were investigated by analyzing the reduction of wall thickness, etc. The results indicate that DLC film is very helpful for improving the qualities of the micro-parts.
基金supported by open research fund from Guangxi Key Laboratory of New Energy and Building Energy Saving, China
文摘Al-doped ZnO thin films were prepared on glass substrate using an ultra-high density target by RF magnetron sputtering at room temperature. The microstructure, surface morphology, optical and electrical properties of AZO thin films were investigated by X-ray diffractometer, scanning electron microscope, UV-visible spectrophotometer, four-point probe method, and Hall-effect measurement system. The results showed that all the films obtained were polycrystalline with a hexagonal structure and average optical transmittance of AZO thin films was over 85 % at different sputtering powers. The sputtering power had a great effect on optoelectronic properties of the AZO thin films, especially on the resistivity. The lowest resistivity of 4.5×10^-4 Ω·cm combined with the transmittance of 87.1% was obtained at sputtering power of 200 W. The optical band gap varied between 3.48 and 3.68 eV.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.10575039） and the Chinese Specialized Research Fund for the Doctoral Program of Higher Education （No.2004057408）.
文摘Large scale homogenous growth of microcrystalline silicon （μ.c-Si：H） on cheap substrates by inductively coupled plasma （ICP） of Ar diluted Sill4 has been studied. From XRD and Raman spectrum, we find that substrates can greatly affect the crystalline orientation, and the μc-Si：H films are comprised of small particles. Thickness detection by surface profilometry shows that the thin μc-Si：H films are homogenous in large scale. Distributions of both ion density and electron temperature are found to be uniform in the vicinity of substrate by means of diagnosis of Langmuir probe. Based on these experimental results, it can be proposed that rough surfaces play important roles in the crystalline network formation and Ar can affect the reaction process and improve the characteristics of μc-Si：H films. Also, ICP reactor can deposit the thin film in large scale.
基金Project (60908023) supported by the National Natural Science Foundation of China
文摘Copper （Cu） doped beryllium （Be） thin films were deposited on silicon substrates by using a simple ion beam sputtering method, which can also realize the varying of Cu doping concentration. Detailed morphological and structural characterizations of the samples clearly disclose a microstructure evolution of films upon doping Cu. Doping Cu can effectively suppress film grain growth, causing a small grain size as well as uniform size distribution. Furthermore, doping Cu affects the crystallographic texture of film, which leads to the formation of more compact film structure. In particular, the surface smoothness of the doped films is significantly improved, which makes them promising candidates for various applications.
文摘Using H 2 diluted silane,series of μc Si∶H films are fabricated at low temperature with VHF PECVD.The thickness measurements reveal that the deposition rates are obviously enhanced with higher plasma excitation frequency or working pressure,but increase firstly and then decrease with the increase of plasma power density.Raman spectra show that the crystallinity and the average grain sizes of the films strongly depend on the temperature of substrate and the concentration of silane.However,the plasma excitation frequency only has effect on the crystallinity,and a maximum occurs during the further increase of plasma excitation frequency.From XRD and TEM experiments,three preferential crystalline orientations (111),(220) and (311) are observed,and the average grain sizes are different for every crystalline orientation.
文摘Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any property separately with the thickness of film, the interaction between particles of different types, the repulsion between particle and boundary, except for the dependence of the variations of mean-square bond length on the thickness of film, which exhibits as a wave trend. What＇s more, the varying trends of mean-square bond length and root-mean-square end-to-end distance can correspond to each other. The density distribution of either component in diblock copolymer film can be controlled and adjusted effectively through its interaction with boundary.
基金Project (2010JQ6008) supported by the Natural Science Foundation of Shaanxi Province,China
文摘Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n（Zn）/n（Ti） on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n（Zn）/n（Ti） typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n（Zn）/n（Ti） leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n（Zn）/n（Ti） of 1/9.3, respectively. The n（Zn）/n（Ti） shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n（Zn）/n（Ti） has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n（Zn）/n（Ti）, the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n（Zn）/n（Ti） but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n（Zn）/n（Ti）=1：9.3.
文摘Tantalum nitride （TAN） and nichrome （NiCr） are the two most common materials used as thin film resistors （TFR） for monolithic microwave integrated circuits （MMIC） based on AlGaN/GaN high electron mobility transistors （HEMTs）. In this study,we compare the reliability of the two materials used as TFRs on a semi-insulation 4H SiC substrate. Through the comparison between NiCr and TaN thin-film resistor materials, we find the square resistor （Rs） of TaN TFR increases as the annealing temperature increases. However, the R s of NiCr TFR shows the opposite trend. We also find the change of the TaN Rs and contacted resistor （Re） is smaller than the NiCr. After O2 plasma exposure in RIE,the TaN R s only decreases 0.7Ω,or about 2.56%, and R c increases 0.1Ω,or about 6.6%, at an annealing temperature of 400℃. In contrast, the NiCr R s and R c show large changes at different annealing temperatures after O2 plasma exposure. In conclusion,TaN is more stable during plasma exposure after 400℃ annealing in N2 ambient.
文摘A novel capacitive microwave MEMS switch with a silicon/metal/dielectric as a membrane is fabricated successfully by bonding and etching-stop process. Its principal, design, and fabricating process are described in detail. A patterned dielectric layer, Ta2O5, with dielectric constant of 24 is reached. Experiment results show this novel structure,where the switch＇s dielectric layer is not prepared on the transmission line, features very low insertion loss. The insertion loss is 0.06dB at 2GHz and lower than 0.5dB in the wider range from De up to 20GHz,especially when the transmission line metal is only 0. 5μm thick.
基金Project(51201187)supported by the National Natural Science Foundation of China
文摘Vanadium carbide/titanium carbide （VC/TiC） superlattice films were synthesized by magnetron sputtering method. The effects of modulation period on the microstructure evolution and mechanical properties were investigated by EDXA, XRD, HRTEM and nano-indentation. The results reveal that the VC/TiC superlattice films form an epitaxial structure when their modulation period is less than a critical value, accompanied with a remarkable increase in hardness. Further increasing the modulation period, the hardness of superlattices decreases slowly to the rule-of-mixture value due to the destruction of epitaxial structures. The XRD results reveal that three-directional strains are generated in superlattices when the epitaxial structure is formed, which may change the modulus of constituent layers. This may explain the remarkable hardness enhancement of VC/TiC superlattices.
