AlN thin films have been grown on R((1-12) surface-cut)-Al2O3, SiO2-glass and C((001) surface-cut)-Al2O3 substrates, by using a reactive-RF-sputter-deposition method. X-ray diffraction (XRD) shows that AlN film has (1...AlN thin films have been grown on R((1-12) surface-cut)-Al2O3, SiO2-glass and C((001) surface-cut)-Al2O3 substrates, by using a reactive-RF-sputter-deposition method. X-ray diffraction (XRD) shows that AlN film has (110) orientation of wurtzite crystal structure for R-Al2O3 and (001) orientation for SiO2-glass and C-Al2O3 substrates. The film thickness was analyzed by Rutherford backscattering spectroscopy (RBS) and it appears that XRD intensity does not show a linear increase with the film thickness but a correlation with the stress, i.e., deviation of the lattice parameter of the film from that of bulk. The film composition and impurities have been analyzed by ion beam techniques. Effects of high-energy ion beams are briefly presented on atomic structure (whether stress relaxation occurs or not), surface morphology and optical properties.展开更多
Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot filament chemical vapor deposition(HFCVD) method. It is notices that the thermal conductivity of the diamond film/aluminum...Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot filament chemical vapor deposition(HFCVD) method. It is notices that the thermal conductivity of the diamond film/aluminum nitride ceramic(DF/AlN) composite has reached 2.04 W/cm·K, 73%greater than that of AlN ceramic. Compared with the measurement of scanning electron microscopy(SEM) and Raman spectroscopy, the influence of diamond films on the thermal conductivity of the composites was pointed out. The adhesion and the stresses of diamond films were also studied. The unusual stability and very good adhesion of diamond films on AlN ceramic substrates obtained are attributed to the formation of aluminum carbide.展开更多
Aluminum Nitride films were grown on and Si (100) substrate by D.C. reactive magnetron sputtering at room temperature. Influence of sputter deposition time on properties of the AlN films was studied. Structural optica...Aluminum Nitride films were grown on and Si (100) substrate by D.C. reactive magnetron sputtering at room temperature. Influence of sputter deposition time on properties of the AlN films was studied. Structural optical and electrical properties of the film were investigated. XRD measurements showed the presence of hexagonal wurtzite structure. The optical reflectance spectra of the film were taken and the band gap calculated varied from 4.35 to 5.3 eV. Finally MIS capacitors were fabricated on silicon substrates and variation of dielectric parameter with deposition time was reported.展开更多
Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further p...Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.展开更多
Columnar nanocrystalline aluminum nitride(cnc-AlN) thin films with(002) orientation and uniform texture have been deposited successfully on large silicon wafers by RF reactive magnetron sputtering.At the optimum sputt...Columnar nanocrystalline aluminum nitride(cnc-AlN) thin films with(002) orientation and uniform texture have been deposited successfully on large silicon wafers by RF reactive magnetron sputtering.At the optimum sputtering parameters, the deposited cnc-AlN thin films show a c-axis preferred orientation with a crystallite size of about 28 nm and surface roughness(RMS) of about 1.29 nm. The cnc-AlN thin films were well transparent with an optical band gap about 4.8 e V, and the residual compressive stress and the defect density in the film have been revealed by Ramon spectroscopy. Moreover, piezoelectric performances of the cnc-AlN thin films executed effectively in a film bulk acoustic resonator structure.展开更多
Plasma-assisted ball milling was carried out on the Al+C3H6N6 system and Al+C_(4)H_(4)N_(4) system,respectively.The phase structure,functional groups and synthesis mechanism were analyzed by XRD and FT-IR,and the diff...Plasma-assisted ball milling was carried out on the Al+C3H6N6 system and Al+C_(4)H_(4)N_(4) system,respectively.The phase structure,functional groups and synthesis mechanism were analyzed by XRD and FT-IR,and the differences in the synthesis process of nano-AlN with different solid nitrogen sources were discussed.The results show that C3H6N6 has a stable triazine ring structure,and its chemical bond is firm and difficult to break,so AlN cannot be synthesized directly by solid-solid reaction at room temperature.However,there are a large number of nitrile groups(-CN)and amino groups(-NH_(2))in C_(4)H_(4)N_(4) molecules.Under the combined action of plasma bombardment and mechanical energy activation,C_(4)H_(4)N_(4) molecules undergo polycondensation and deamination,so that the ball milling tank is filled with a large number of active nitrogen-containing groups such as N=,≡N,etc.These groups and ball milling activated Al can synthesize nano-AlN at room temperature,with a conversion rate of 92%.SEM,DSC/TG analysis showed that the powder obtained by ball milling was formed by soft agglomeration of many fine primary particles about 50–80 nm.The surface morphology of the powder was loose and porous,and it had strong activity.After annealing at 800℃,the conversion rate of the Al+C_(4)H_(4)N_(4) system reached 99%.展开更多
文摘AlN thin films have been grown on R((1-12) surface-cut)-Al2O3, SiO2-glass and C((001) surface-cut)-Al2O3 substrates, by using a reactive-RF-sputter-deposition method. X-ray diffraction (XRD) shows that AlN film has (110) orientation of wurtzite crystal structure for R-Al2O3 and (001) orientation for SiO2-glass and C-Al2O3 substrates. The film thickness was analyzed by Rutherford backscattering spectroscopy (RBS) and it appears that XRD intensity does not show a linear increase with the film thickness but a correlation with the stress, i.e., deviation of the lattice parameter of the film from that of bulk. The film composition and impurities have been analyzed by ion beam techniques. Effects of high-energy ion beams are briefly presented on atomic structure (whether stress relaxation occurs or not), surface morphology and optical properties.
文摘Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot filament chemical vapor deposition(HFCVD) method. It is notices that the thermal conductivity of the diamond film/aluminum nitride ceramic(DF/AlN) composite has reached 2.04 W/cm·K, 73%greater than that of AlN ceramic. Compared with the measurement of scanning electron microscopy(SEM) and Raman spectroscopy, the influence of diamond films on the thermal conductivity of the composites was pointed out. The adhesion and the stresses of diamond films were also studied. The unusual stability and very good adhesion of diamond films on AlN ceramic substrates obtained are attributed to the formation of aluminum carbide.
文摘Aluminum Nitride films were grown on and Si (100) substrate by D.C. reactive magnetron sputtering at room temperature. Influence of sputter deposition time on properties of the AlN films was studied. Structural optical and electrical properties of the film were investigated. XRD measurements showed the presence of hexagonal wurtzite structure. The optical reflectance spectra of the film were taken and the band gap calculated varied from 4.35 to 5.3 eV. Finally MIS capacitors were fabricated on silicon substrates and variation of dielectric parameter with deposition time was reported.
文摘Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.
文摘Columnar nanocrystalline aluminum nitride(cnc-AlN) thin films with(002) orientation and uniform texture have been deposited successfully on large silicon wafers by RF reactive magnetron sputtering.At the optimum sputtering parameters, the deposited cnc-AlN thin films show a c-axis preferred orientation with a crystallite size of about 28 nm and surface roughness(RMS) of about 1.29 nm. The cnc-AlN thin films were well transparent with an optical band gap about 4.8 e V, and the residual compressive stress and the defect density in the film have been revealed by Ramon spectroscopy. Moreover, piezoelectric performances of the cnc-AlN thin films executed effectively in a film bulk acoustic resonator structure.
基金The study was supported by the Education and Research Project for Young and Middle-Aged Teachers in Fujian Province(JAT201167).
文摘Plasma-assisted ball milling was carried out on the Al+C3H6N6 system and Al+C_(4)H_(4)N_(4) system,respectively.The phase structure,functional groups and synthesis mechanism were analyzed by XRD and FT-IR,and the differences in the synthesis process of nano-AlN with different solid nitrogen sources were discussed.The results show that C3H6N6 has a stable triazine ring structure,and its chemical bond is firm and difficult to break,so AlN cannot be synthesized directly by solid-solid reaction at room temperature.However,there are a large number of nitrile groups(-CN)and amino groups(-NH_(2))in C_(4)H_(4)N_(4) molecules.Under the combined action of plasma bombardment and mechanical energy activation,C_(4)H_(4)N_(4) molecules undergo polycondensation and deamination,so that the ball milling tank is filled with a large number of active nitrogen-containing groups such as N=,≡N,etc.These groups and ball milling activated Al can synthesize nano-AlN at room temperature,with a conversion rate of 92%.SEM,DSC/TG analysis showed that the powder obtained by ball milling was formed by soft agglomeration of many fine primary particles about 50–80 nm.The surface morphology of the powder was loose and porous,and it had strong activity.After annealing at 800℃,the conversion rate of the Al+C_(4)H_(4)N_(4) system reached 99%.
