Influence of SiO2 Nanosphere on the Performance of p+ Layer Formed by B Diffusion from Boric Acid Solution
YANG Nannan, SHEN Honglie, JIANG Ye, JIN Lei, LI Jinze, WU Wenwen, YU Shuanglong, YANG Yan
Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016
Abstract: In order to improve the quality of B doped layer by diffusion, a novel boron source mixed with SiO2 nanosphere was introduced. Scanning electronic microscopy, four probe method and minority carrier lifetime measurement were adopted to study the influence of SiO2 nanosphere on the performance of p+ layer formed by B diffusion from boric acid solution. It was found that the thickness of boron rich layer (BRL) decreased from 130 nm to 15 nm compared with that produced without addition of SiO2 nanosphere. At the same time, the uniformity of diffusion increased from 88.17% to 96.79%. In addition, junction depth decreased slightly and minority carrier lifetime in the samples increased apparently after using mixed boric acid solution with SiO2 nanosphere. All the results above indicated that SiO2 nanosphere could evidently enhance the property of the p+ layer formed by liquid B source diffusion from boric acid solution.
杨楠楠, 沈鸿烈, 蒋晔, 金磊, 李金泽, 吴文文, 余双龙, 杨艳. 二氧化硅纳米球对硼酸源扩散形成p+硅层性能的影响*[J]. 《材料导报》期刊社, 2017, 31(12): 11-14.
YANG Nannan, SHEN Honglie, JIANG Ye, JIN Lei, LI Jinze, WU Wenwen, YU Shuanglong, YANG Yan. Influence of SiO2 Nanosphere on the Performance of p+ Layer Formed by B Diffusion from Boric Acid Solution. Materials Reports, 2017, 31(12): 11-14.
1 Bruschi D L, Moehlecke A, Zanesco I, et al. Development of solar cells in n-type silicon with emitter formed with boron[J]. Materia-Rio de Janeiro,2010,16(3):776. 2 Kim D S, et al. Silicon solar cells with back surface field formed using boric acid[C]//22nd European PVSEC.Milan,2007. 3 Singh G. Fabrication of c-Si solar cells using boric acid as a spin-on dopant for back surface field[J]. RSC Adv,2014,4(9):4225. 4 Moehlecke A, Osório V D C, Zanesco I. Analysis of thin bifacial si-licon solar cells with locally diffused and selective back surface field[J]. Mater Res,2014,17(5):1328. 5 Solanki C S, Singha B. Impact of a boron rich layer on minority carrier lifetime degradation in boron spin-on dopant diffused n-type crystalline silicon solar cells[J]. Semiconductor Sci Technol,2016,31(3):35009. 6 Cho Y J, Chang H S. Enhanced boron gettering effect of n-type solar grade Si wafers by in situ oxidation[J]. Metals Mater Int,2013,19(6):1377. 7 Kessler M A, Ohrdes T, Wolpensinger B, et al. Characterisation and implications of the boron rich layer resulting from open-tube li-quid source BBr3 boron diffusion processes[C]//Photovoltaic Specialists Conference (PVSC),34th IEEE. Philadelphia,2009:001556. 8 Long T J, Xu G Q, Yang X S, et al. Wet-chemical removal of boron-rich surface layer on boron diffused silicon[J].J Mater Sci Eng,2015,33(1):9(in Chinese). 龙腾江, 徐冠群, 杨晓生,等. 湿法去除N型硅硼扩散过程形成的富硼层[J]. 材料科学与工程学报,2015,33(1):9. 9 Ryu K, Upadhyaya A, Upadhyaya V, et al. High efficiency large area n-type front junction silicon solar cells with boron emitter formed by screen printing technology[J]. Prog Photovoltaics Res Applications,2015,23(1):119. 10 Stöber W, Fink A, Bohn E. Controlled growth of monodisperse si-lica spheres in the micron size range[J].J Colloid Interface Sci,1968,26(1):62. 11 Choi J Y, Alford T L, Honsberg C B. Solvent-controlled spin-coa-ting method for large-scale area deposition of two-dimensional silica nanosphere assembled layers[J]. Langmuir,2014,30(20):5732. 12 Das A, Kim D S, Nakayashiki K, et al. Boron diffusion with boric acid for high efficiency silicon solar cells[J].J Electrochem Soc,2010,157(6):H684. 13 Kim C, Park S, Kim Y D, et al. Properties of boron-rich layer formed by boron diffusion in n-type silicon[J]. Thin Solid Films,2014,564(8):253. 14 Kessler M A, et al. Charge carrier lifetime degradation in Cz silicon through the formation of a boron-rich layer during BBr3 diffusion processes[J]. Semiconductor Sci Technol,2010,25(5):966. 15 Zhou C L, Wang W J. Lifetime measurement for minority carrier of crytalline silicon solar cells[J]. China Measurement Technol,2007,33(6):25(in Chinese). 周春兰, 王文静. 晶体硅太阳能电池少子寿命测试方法[J]. 中国测试技术,2007,33(6):25.