SiC粉体表面SiO_(2)氧化层对其浆料粘度、流变性产生的影响一直是胶态成型技术关注的问题。采用NaOH、KOH和Na_(2)CO_(3)三种不同强度的碱性溶液对SiC粉体进行处理,考察碱性溶液对SiO_(2)氧化层的活化以及对粉体分散稳定性产生的影响。Z...SiC粉体表面SiO_(2)氧化层对其浆料粘度、流变性产生的影响一直是胶态成型技术关注的问题。采用NaOH、KOH和Na_(2)CO_(3)三种不同强度的碱性溶液对SiC粉体进行处理,考察碱性溶液对SiO_(2)氧化层的活化以及对粉体分散稳定性产生的影响。Zeta电位测试表明,中性时Na_(2)CO_(3)处理后粉体表面的电位绝对值比酸洗粉体提高了16.8 mV,pH值为10时达到67.8 m V。所制备固相含量为35 vol%的浆料,粘度低、稳定性好。因此,适度活化SiC粉体表面氧化层有助于改善浆料的流变性能。展开更多
Al-doped ZnO thin film （AZO） is used as a subcontact layer in 6H-SiC photoconductive semiconductor switches （PCSSs） to reduce the on-state resistance and optimize the device structure. Our photoconductive test sho...Al-doped ZnO thin film （AZO） is used as a subcontact layer in 6H-SiC photoconductive semiconductor switches （PCSSs） to reduce the on-state resistance and optimize the device structure. Our photoconductive test shows that the onstate resistance of lateral PCSS with an n＋-AZO subcontact layer is 14.7% lower than that of PCSS without an n＋-AZO subcontact layer. This occurs because a heavy-doped AZO thin film can improve Ohmic contact properties, reduce contact resistance, and alleviate Joule heating. Combined with the high transparance characteristic at 532 nm of AZO film, vertical structural PCSS devices are designed and their structural superiority is discussed. This paper provides a feasible route for fabricating high performance SiC PCSS by using conductive and transparent ZnO-based materials.展开更多
In this paper, a new structure of a 4H-SiC bipolar junction transistor （BJT） with a buried layer （BL） in the base is presented. The current gain shows an approximately 100% increase compared with that of the conve...In this paper, a new structure of a 4H-SiC bipolar junction transistor （BJT） with a buried layer （BL） in the base is presented. The current gain shows an approximately 100% increase compared with that of the conventional structure. This is attributed to the creation of a built-in electric field for the minority carriers to transport in the base which is explained based on 2D device simulations. The optimized design of the buried layer region is also considered by numeric simulations.展开更多
SiC particulate reinforced 6066 aluminium alloy metal matrix composites (MMCs) were prepared by multi layer spray forming. The preparation technology and process parameters were discussed. It is shown that SiC particu...SiC particulate reinforced 6066 aluminium alloy metal matrix composites (MMCs) were prepared by multi layer spray forming. The preparation technology and process parameters were discussed. It is shown that SiC particulate can be continuously and evenly fed and co deposited in the spray forming process. The reciprocally scanning movement of spraying system can make the SiC particulates distribute homogeneously in the composite. The ratio of SiC particulates captured by the metal matrix is influenced by process parameters, especially the metal flow rate. 6066/SiC p composite preforms of d 300 mm×540 mm and tubes with a size of up to d 650/ d 300 mm×1 000 mm were made by the same process. After extrusion and T6 heat treatment, the multi layer spray deposited 6066/SiC p composites can achieve improved properties. [展开更多
Annealing effects on structural and compositional performances of A1203 thin films on 4H-SiC substrates are studied comprehensively. The Al2O3 films are grown by atomic layer deposition through using trimethylaluminum...Annealing effects on structural and compositional performances of A1203 thin films on 4H-SiC substrates are studied comprehensively. The Al2O3 films are grown by atomic layer deposition through using trimethylaluminum and H2O as precursors at 300 ℃, and annealed at various temperatures in ambient N2 for 1 min. The Al2O3 film transits from amorphous phase to crystalline phase as annealing temperature increases from 750 ℃ to 768 ℃. The refractive index increases with annealing temperature rising, which indicates that densification occurs during annealing. The densification and grain formation of the film upon annealing are due to crystallization which is relative with second-nearest-neighbor coordination variation according to the x-ray photoelectron spectroscopy （XPS）. Although the binding energies of Al 2p and O ls increase together during crystallization, separations between Al 2p and O ls are identical between as-deposited and annealed sample, which suggests that the nearest-neighbour coordination is similar.展开更多
文摘SiC粉体表面SiO_(2)氧化层对其浆料粘度、流变性产生的影响一直是胶态成型技术关注的问题。采用NaOH、KOH和Na_(2)CO_(3)三种不同强度的碱性溶液对SiC粉体进行处理,考察碱性溶液对SiO_(2)氧化层的活化以及对粉体分散稳定性产生的影响。Zeta电位测试表明,中性时Na_(2)CO_(3)处理后粉体表面的电位绝对值比酸洗粉体提高了16.8 mV,pH值为10时达到67.8 m V。所制备固相含量为35 vol%的浆料,粘度低、稳定性好。因此,适度活化SiC粉体表面氧化层有助于改善浆料的流变性能。
基金Project supported by the Innovation Program of the Shanghai Institute of Ceramics(Grant No.Y39ZC1110G)the Innovation Program of the Chinese Academy of Sciences(Grant No.KJCX2-EW-W10)+3 种基金the Industry–Academic Joint Technological Innovations Fund Project of Jiangsu Province,China(Grant No.BY2011119)the Natural Science Foundation of Shanghai(Grant No.14ZR1419000)the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.61404146)the National High-tech R&D Program of China(Grant Nos.2013AA031603 and 2014AA032602)
文摘Al-doped ZnO thin film （AZO） is used as a subcontact layer in 6H-SiC photoconductive semiconductor switches （PCSSs） to reduce the on-state resistance and optimize the device structure. Our photoconductive test shows that the onstate resistance of lateral PCSS with an n＋-AZO subcontact layer is 14.7% lower than that of PCSS without an n＋-AZO subcontact layer. This occurs because a heavy-doped AZO thin film can improve Ohmic contact properties, reduce contact resistance, and alleviate Joule heating. Combined with the high transparance characteristic at 532 nm of AZO film, vertical structural PCSS devices are designed and their structural superiority is discussed. This paper provides a feasible route for fabricating high performance SiC PCSS by using conductive and transparent ZnO-based materials.
文摘In this paper, a new structure of a 4H-SiC bipolar junction transistor （BJT） with a buried layer （BL） in the base is presented. The current gain shows an approximately 100% increase compared with that of the conventional structure. This is attributed to the creation of a built-in electric field for the minority carriers to transport in the base which is explained based on 2D device simulations. The optimized design of the buried layer region is also considered by numeric simulations.
文摘SiC particulate reinforced 6066 aluminium alloy metal matrix composites (MMCs) were prepared by multi layer spray forming. The preparation technology and process parameters were discussed. It is shown that SiC particulate can be continuously and evenly fed and co deposited in the spray forming process. The reciprocally scanning movement of spraying system can make the SiC particulates distribute homogeneously in the composite. The ratio of SiC particulates captured by the metal matrix is influenced by process parameters, especially the metal flow rate. 6066/SiC p composite preforms of d 300 mm×540 mm and tubes with a size of up to d 650/ d 300 mm×1 000 mm were made by the same process. After extrusion and T6 heat treatment, the multi layer spray deposited 6066/SiC p composites can achieve improved properties. [
基金Project supported by the National Basic Research Program of China(Grant No.2015CB759600)the National Natural Science Foundation of China(Grant Nos.61474113,61574140,and 61274007)+1 种基金the Beijing Nova Program,China(Grant No.xx2016071)the CAEP Microsystem and THz Science and Technology Foundation(Grant No.CAEPMT201502)
文摘Annealing effects on structural and compositional performances of A1203 thin films on 4H-SiC substrates are studied comprehensively. The Al2O3 films are grown by atomic layer deposition through using trimethylaluminum and H2O as precursors at 300 ℃, and annealed at various temperatures in ambient N2 for 1 min. The Al2O3 film transits from amorphous phase to crystalline phase as annealing temperature increases from 750 ℃ to 768 ℃. The refractive index increases with annealing temperature rising, which indicates that densification occurs during annealing. The densification and grain formation of the film upon annealing are due to crystallization which is relative with second-nearest-neighbor coordination variation according to the x-ray photoelectron spectroscopy （XPS）. Although the binding energies of Al 2p and O ls increase together during crystallization, separations between Al 2p and O ls are identical between as-deposited and annealed sample, which suggests that the nearest-neighbour coordination is similar.
