Dry etching of 6H silicon carbide （6H-SiC） wafers in a C4Fs/Ar dual-frequency capacitively coupled plasma （DF-CCP） was investigated. Atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS） wer...Dry etching of 6H silicon carbide （6H-SiC） wafers in a C4Fs/Ar dual-frequency capacitively coupled plasma （DF-CCP） was investigated. Atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS） were used to measure the SiC surface structure and compositions, respectively. Optical emission spectroscopy （OES） was used to measure the relative concentration of F radicals in the plasma. It was found that the roughness of the etched SiC surface and the etching rate are directly related to the power of low-frequency （LF） source. At lower LF power, a smaller surface roughness and a lower etching rate are obtained due to weak bombardment of low energy ions on the SiC wafers. At higher LF power the etching rate can be efficiently increased, but the surface roughness increases too. Compared with other plasma dry etching methods, the DF-CCP can effectively inhibit CχFγ films＇ deposition, and reduce surface residues.展开更多
Patterned flow sensor cell consisting of single-walled carbon nanotubes (SWCNTs) network and polydimethylsiloxane (PDMS) are fabricated,based on the process of vacuum filtration,photolithography,and plasma etching.The...Patterned flow sensor cell consisting of single-walled carbon nanotubes (SWCNTs) network and polydimethylsiloxane (PDMS) are fabricated,based on the process of vacuum filtration,photolithography,and plasma etching.The sensor cell is a composite thin film and packaged to form a flow sensor,and then tested in different flow rates with different liquids,such as deionized (DI) water and NaCl solution.The induced-voltage increases with increasing flowing velocity and liquid concentration.The relation between induced-voltage and sensor cell conductivity is tested in the same liquid at the same flow rate.The higher the conductivity is,the higher the induced-voltage is.Some of the SWCNTs are fixed in the PDMS matrix,simultaneously some of them protrude above the composite thin film,which are exposed to the liquid and contribute to the voltage generation.The fabrication method can make the flow sensor scaled down to dimensions on the order of micrometers,which makes it suitable in very small liquid volumes.展开更多
基金supported by National Natural Science Foundation of China （Nos. 10975105, 11275136, 10975106, 11175126, 11204266 and 11075114） the National Magnetic Confinement Fusion Science Program of China （Nos. 2010GB106000, 2010GB106009）, the Open Project of State Key Laboratory of Functional Materials for Information and Qing Lan Project, a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and the Program for graduates Research ＆ Innovation in University of Jiangsu Province, China （No. CX10B-031Z）
文摘Dry etching of 6H silicon carbide （6H-SiC） wafers in a C4Fs/Ar dual-frequency capacitively coupled plasma （DF-CCP） was investigated. Atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS） were used to measure the SiC surface structure and compositions, respectively. Optical emission spectroscopy （OES） was used to measure the relative concentration of F radicals in the plasma. It was found that the roughness of the etched SiC surface and the etching rate are directly related to the power of low-frequency （LF） source. At lower LF power, a smaller surface roughness and a lower etching rate are obtained due to weak bombardment of low energy ions on the SiC wafers. At higher LF power the etching rate can be efficiently increased, but the surface roughness increases too. Compared with other plasma dry etching methods, the DF-CCP can effectively inhibit CχFγ films＇ deposition, and reduce surface residues.
基金the National High-Tech Research & Development Program of China (2007AA04Z348)China Postdoctoral Science Foundation (20080440139)
文摘Patterned flow sensor cell consisting of single-walled carbon nanotubes (SWCNTs) network and polydimethylsiloxane (PDMS) are fabricated,based on the process of vacuum filtration,photolithography,and plasma etching.The sensor cell is a composite thin film and packaged to form a flow sensor,and then tested in different flow rates with different liquids,such as deionized (DI) water and NaCl solution.The induced-voltage increases with increasing flowing velocity and liquid concentration.The relation between induced-voltage and sensor cell conductivity is tested in the same liquid at the same flow rate.The higher the conductivity is,the higher the induced-voltage is.Some of the SWCNTs are fixed in the PDMS matrix,simultaneously some of them protrude above the composite thin film,which are exposed to the liquid and contribute to the voltage generation.The fabrication method can make the flow sensor scaled down to dimensions on the order of micrometers,which makes it suitable in very small liquid volumes.
