退火对铝诱导结晶锗薄膜的影响及其机理
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摘要
为实现在Si衬底上制备GaInP/GaInAs/Ge三结太阳电池,本工作尝试利用磁控溅射和常规退火技术,采用铝诱导结晶(AIC)法在(100)晶面单晶硅衬底上制备Ge薄膜,利用金相显微镜(Metallographic microscopy)、X射线衍射仪(XRD)、拉曼光谱仪(Raman)对其进行表征。分析了铝诱导过程中退火时间和退火温度对Ge薄膜结晶性的影响,发现退火温度越低、时间越长,制备的薄膜质量越好,确定了Ge薄膜晶化的最低退火温度为250℃,并在该温度下成功制备出了晶粒尺寸超过100nm、Ge(111)晶面择优取向度达到99%以上的Ge薄膜。
For the sake of fabricating GaInP/GaInAs/Ge triple-junction solar cell on silicon substrate,the present work made an attempt to prepare Ge film on a(100)monocrystalline silicon substrate following the strategy of aluminum-induced crystallization(AIC)by magnetron sputtering and conventional annealing method.The resultant samples were analyzed by metallographic microscopy,XRD and Raman spectroscopy,so as to investigate the effects of annealing time and annealing temperature during the process of AIC on Ge crystallinity.Our experiment confirmed the improved Ge film quality by adopting lower annealing temperatures and longer annealing durations.The minimum annealing temperature for the aluminum-induced Ge film crystallization was determined to be 250 ℃,under which a Ge film with a grain size larger than 100 nm and preferred orientation of Ge(111)facet higher than 99%was successfully obtained.
For the sake of fabricating GaInP/GaInAs/Ge triple-junction solar cell on silicon substrate,the present work made an attempt to prepare Ge film on a(100)monocrystalline silicon substrate following the strategy of aluminum-induced crystallization(AIC)by magnetron sputtering and conventional annealing method.The resultant samples were analyzed by metallographic microscopy,XRD and Raman spectroscopy,so as to investigate the effects of annealing time and annealing temperature during the process of AIC on Ge crystallinity.Our experiment confirmed the improved Ge film quality by adopting lower annealing temperatures and longer annealing durations.The minimum annealing temperature for the aluminum-induced Ge film crystallization was determined to be 250 ℃,under which a Ge film with a grain size larger than 100 nm and preferred orientation of Ge(111)facet higher than 99%was successfully obtained.
引文
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13 孙钦钦.铝诱导晶化法制备高质量多晶Si、SiGe材料的研究[D].厦门:厦门大学,2014.
2 Wolf M.Limitations and possibilities for improvement of photovoltaic solar energy converters:PartⅠ:Considerations for earth’s surface operation[J].Proceedings of the Ire,1960,48(7):1246.
3 MartíA,Araújo G L.Limiting efficiencies for photovoltaic energy conversion in multigap systems[J].Solar Energy Materials&Solar Cells,1996,43(2):203.
4 Green M A,Keevers M J,Concha Ramon B,et al.Improvements in sunlight to electricity conversion efficiency:Above 40%for direct sunlight and over 30%for global[C]∥European Photovoltaic Solar Energy Conference 2015,Hamburg,2015.
5 Gao W,Zhang B,Xue C,et al.Ultra-thin GaInP/GaInAs/Ge solar cells[J].Chinese Journal of Power Sources,2014,38(6):1069(in Chinese).高伟,张宝,薛超,等.超薄GaInP/GaInAs/Ge太阳电池研究[J].电源技术,2014,38(6):1069.
6 Jin C B,Yang J E,Jo M H.Shape-controlled growth of single-crystalline Ge nanostructures[J].Applied Physics Letters,2006,88(19):193105.
7 Hamaya K,Itoh H,Nakatsuka O,et al.Ferromagnetism and electronic structures of nonstoichiometric Heusler-alloy Fe3-x MnxSi epilayers grown on Ge(111)[J].Physical Review Letters,2009,102(13):137204.
8 Fukata N,Sato K,Mitome M,et al.Doping and Raman characterization of boron and phosphorus atoms in germanium nanowires[J].ACS Nano,2010,4(7):3807.
9 Wang P,Li X,Liu H,et al.High(111)orientation poly-Ge film fabricated by Al induced crystallization without the introduction of AlOx,interlayer[J].Materials Research Bulletin,2015,72:60.
10 Lee D W,Bhopal M F,Lee S H.Crystallized Si layer properties of novel aluminum-induced crystallization[J].Materials Letters,2016,174:217.
11 Zhang Y T,Xu Z C,Li F H,et al.Morphology and preferential orientation of electro-deposited Cu/Si thin films[J].Journal of Synthetic Crystals,2006,35(4):728(in Chinese).张雅婷,徐章程,李菲晖,等.Si基上电沉积Cu薄膜的形貌与择优取向[J].人工晶体学报,2006,35(4):728.
12 Wang C L,Miao S F,Fan D W,et al.Mechanism of low temperature growth of M-induced polycrystalline Si film[J].Chinese Journal of Vacuum Science and Technology,2013,33(11):1139(in Chinese).王成龙,苗树翻,范多旺,等.铝诱导晶化低温制备多晶硅薄膜的机理研究[J].真空科学与技术学报,2013,33(11):1139.
13 孙钦钦.铝诱导晶化法制备高质量多晶Si、SiGe材料的研究[D].厦门:厦门大学,2014.