A1GaN/GaN high electron-mobility transistors （HEMTs） with 5 nm A1N passivation by plasma en- hanced atomic layer deposition （PEALD） were fabricated, covered by 50 nm SiNx which was grown by plasma enhanced chemica...A1GaN/GaN high electron-mobility transistors （HEMTs） with 5 nm A1N passivation by plasma en- hanced atomic layer deposition （PEALD） were fabricated, covered by 50 nm SiNx which was grown by plasma enhanced chemical vapor deposition （PECVD）. With PEALD A1N passivation, current collapse was suppressed more effectively and the devices show better subthreshold characteristics. Moreover, the insertion of A1N increased the RF transconductance, which lead to a higher cut-off frequency. Temperature dependence of DC characteristics demonstrated that the degradations of drain current and maximum transconductance at elevated temperatures for the A1N/SiNx passivated devices were much smaller compared with the devices with SiNx passivation, indicating that PEALD A1N passivation can improve the high temperature operation of the A1GaN/GaN HEMTs.展开更多
In this paper, an N-doped titanium oxide （TiO2） photocatalyst is deposited by a plasma-enhanced atomic layer deposition （PEALD） system through the in-situ doping method. X-ray photoelectron spectroscopy （XPS） an...In this paper, an N-doped titanium oxide （TiO2） photocatalyst is deposited by a plasma-enhanced atomic layer deposition （PEALD） system through the in-situ doping method. X-ray photoelectron spectroscopy （XPS） analysis indicates that substitutional nitrogen atoms （-395.9 eV） with 1 atom% are effectively doped into TiO2 films. UV-VIS spectrometry shows that the in-situ nitrogen doping method indeed enhances the visible-activity of TiO2 films in the 425-550 nm range, and the results of the performance tests of the N-doped TiO2 films also imply that the photocatalysis activity is improved by in-situ doping. The in-situ doping mechanism of the N-doped TiO2 film is suggested according to the XPS results and the typical atomic layer deposition process.展开更多
In this work,the GaN thin films were directly deposited on multilayer graphene(MLG)by plasma-enhanced atomic layer deposition.The deposition was carried out at a low temperature using triethylgallium(TEGa)precursor an...In this work,the GaN thin films were directly deposited on multilayer graphene(MLG)by plasma-enhanced atomic layer deposition.The deposition was carried out at a low temperature using triethylgallium(TEGa)precursor and Ar/N2/H2 plasma.Chemical properties of the bulk GaN and GaN-graphene interface were analyzed using X-ray photoelectron spectroscopy.The sharp interface between GaN and graphene was verified via X-ray reflectivity and transmission electron microscope.The microstructures and the nucleation behaviors of the GaN grown on graphene have been also studied.The results of grazing incidence X-ray diffraction and Raman spectrum indicate that the as-deposited sample is polycrystalline with wurtzite structure and has a weakly tensile stress.Optical properties of the sample were investigated by photoluminescence(PL)at room temperature.The successful growth of GaN on MLG at a low temperature opens up the possibility of ameliorating the performance of electronic and optical devices based on GaN/graphene heterojunction.展开更多
基金National Ministry of Science and Technology“13thFive-Year”Key Research and Development Program Sub Project for High Performance Computing(2016YFB0200205)2018 Shanghai Public R&D Service Center Construction Project(18DZ2295400)
基金Project supported by the National Natural Science Foundation of China(No.60890192)
文摘A1GaN/GaN high electron-mobility transistors （HEMTs） with 5 nm A1N passivation by plasma en- hanced atomic layer deposition （PEALD） were fabricated, covered by 50 nm SiNx which was grown by plasma enhanced chemical vapor deposition （PECVD）. With PEALD A1N passivation, current collapse was suppressed more effectively and the devices show better subthreshold characteristics. Moreover, the insertion of A1N increased the RF transconductance, which lead to a higher cut-off frequency. Temperature dependence of DC characteristics demonstrated that the degradations of drain current and maximum transconductance at elevated temperatures for the A1N/SiNx passivated devices were much smaller compared with the devices with SiNx passivation, indicating that PEALD A1N passivation can improve the high temperature operation of the A1GaN/GaN HEMTs.
基金supported by the National Science and Technology Major Project of China(No.2009ZX02037-003)China Postdoctoral Science Foundation(No.2011M500996)the Opening Project of Key Laboratory of Microelectronics Devices&Integrated Technology,Institute of Microelectronics,Chinese Academy of Sciences
文摘In this paper, an N-doped titanium oxide （TiO2） photocatalyst is deposited by a plasma-enhanced atomic layer deposition （PEALD） system through the in-situ doping method. X-ray photoelectron spectroscopy （XPS） analysis indicates that substitutional nitrogen atoms （-395.9 eV） with 1 atom% are effectively doped into TiO2 films. UV-VIS spectrometry shows that the in-situ nitrogen doping method indeed enhances the visible-activity of TiO2 films in the 425-550 nm range, and the results of the performance tests of the N-doped TiO2 films also imply that the photocatalysis activity is improved by in-situ doping. The in-situ doping mechanism of the N-doped TiO2 film is suggested according to the XPS results and the typical atomic layer deposition process.
基金supported financially by the National Natural Science Foundation of China (No.110751402347)the Beijing Natural Science Foundation (Nos.4173077 and 2184112)+2 种基金the Fundamental Research Funds for the Central Universities,China (Nos.FRF-BR-16-018A,FRF-TP-17-022A1,FRF-TP-17-069A1 and 06400071)the China Postdoctoral Science Foundation (No. 2018M631333)the Youth Innovation Promotion Association of Chinese Academy of Sciences (No.2015387)
文摘In this work,the GaN thin films were directly deposited on multilayer graphene(MLG)by plasma-enhanced atomic layer deposition.The deposition was carried out at a low temperature using triethylgallium(TEGa)precursor and Ar/N2/H2 plasma.Chemical properties of the bulk GaN and GaN-graphene interface were analyzed using X-ray photoelectron spectroscopy.The sharp interface between GaN and graphene was verified via X-ray reflectivity and transmission electron microscope.The microstructures and the nucleation behaviors of the GaN grown on graphene have been also studied.The results of grazing incidence X-ray diffraction and Raman spectrum indicate that the as-deposited sample is polycrystalline with wurtzite structure and has a weakly tensile stress.Optical properties of the sample were investigated by photoluminescence(PL)at room temperature.The successful growth of GaN on MLG at a low temperature opens up the possibility of ameliorating the performance of electronic and optical devices based on GaN/graphene heterojunction.
