Characteristics of dual-frequency capacitively coupled SF_6/O_2 plasma and plasma texturing of multi-crystalline silicon
Characteristics of dual-frequency capacitively coupled SF_6/O_2 plasma and plasma texturing of multi-crystalline silicon作者机构:Provincial Key Laboratory of Thin Films School of Physical Science and Technology Soochow University Canadian Solar Inc.China
出 版 物:《Chinese Physics B》 (中国物理B(英文版))
年 卷 期:2014年第23卷第6期
页 面:361-369页
核心收录:
学科分类:07[理学] 070204[理学-等离子体物理] 0702[理学-物理学]
基 金:supported by the Prospective Project of Industry–University–Research Institution of Jiangsu Province,China(Grant No.BY2010125) the National Natural Science Foundation of China(Grant No.11175127)
主 题:dual frequency capacitively coupled plasma plasma texturing multi-crystalline silicon electrondensity
摘 要:Due to it being environmentally friendly, much attention has been paid to the dry plasma texturing technique serving as an alternative candidate for multicrystalline silicon (mc-Si) surface texturing. In this paper, capacitively coupled plasma (CCP) driven by a dual frequency (DF) of 40.68 MHz and 13.56 MHz is first used for plasma texturing of mc-Si with SF6/O2 gas mixture. Using a hairpin resonant probe and optical emission techniques, DF-CCP characteristics and their influence on mc-silicon surface plasma texturing are investigated at different flow rate ratios, pressures, and radio-frequency (RF) input powers. Experimental results show that suitable plasma texturing of mc-silicon occurs only in a narrow range of plasma parameters, where electron density ne must be larger than 6.3 x 109 cm-3 and the spectral intensity ratio of the F atom to that of the O atom ([F]/[O]) in the plasma must be between 0.8 and 0.3. Out of this range, no cone-like structure is formed on the mc-silicon surface. In our experiments, the lowest reflectance of about 7.3% for mc-silicon surface texturing is obtained at an [F]/[O] of 0.5 and ne of 6.9 × 109 cm-3.