microstructure Development of multicrystal silicon ingot for solar battery by the control of twinning

孪生控制太阳能电池用多晶硅锭的显微组织开发

基本信息

批准号：
17560652
负责人：
MIYAHARA Hirofumi
金额：
$ 2.24万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560652/
关键词：
twin boundary multicrystal silicon faceted growth Solar battery crystal growth undercooling photoelectric transformation diffusion length of carrier 太陽光発電

项目摘要

The mechanisms of columnar structure growth of the multicrystal silicon and influence of twining on the microstructure formation are investigated to the development of the photoelectric transformation efficiency and the productivity of solar battery cell fabricated by the unidirectional solidification technique.The solar battery-grade high-purity silicon crystals has been solidified in quartz crucibles, whose inside diameter is 20 mm and the height is 100 mm, at the velocity of 0.075 to 9.6 mm/s and a temperature gradient of 20K/cm by using the Bridgman type furnace at the Ar atmosphere.The columnar structures are observed parallel to the heat flow direction in a velocity about 1.2 mm/min, and the larger size grains are obtained at the lower solidification speed. Twin boundaries, which have the crystal orientation relationship of sigma 3, grow parallel to the heat flow direction. Therefore, the undercoolings for the growth were measured by using seeds of <111> and <101> and twin introduced <211> crystals. The <111> specimens has larger undercooling of 2.5〜5.5K and <101> has smaller. However, twin introduced <211> specimens has lowest undercooling of 0.5〜3.5K. Since it is also revealed that the solidification velocity of twin introduced <211> crystal is higher by the molecular dynamics simulation, the reentrant corner of twin boundary becomes kink site and can give an advantage to the faceted growth and the development of grain size.The silicon crystal grows to the orientation between <211> to <101> along to the crucible bottom. And the grain size was enlarged by increasing the undercooling as well as the faster solidification velocity of 0.6 to 2.4mm/min in the initial solidification region. However, in order to continue such large gain size, it is necessary to reduce the velocity to 0.12 to 0.3mm/min until middle and final solidification stage.

研究了柱状硅的柱状结构生长的机制以及双胞胎对微观结构形成的影响，以发展光电转化效率的发展以及通过单向固化技术制造的太阳能电池电池的生产力。通过在AR大气中使用Bridgman型炉子的速度为0.075至9.6 mm/s，温度梯度为20K/cm。观察到柱状结构在约1.2 mm/min的速度下平行于热流动方向，并且在较大的固体速度下获得较大的尺寸粒度。具有Sigma 3的晶体取向关系的双边界与热流动方向平行。因此，通过使用<111>和<101>和Twin引入<211>晶体的种子来测量生长的过冷底。 <111>标本的底冷较大2.5-5.5k和<101>的过冷较小。但是，Twin引入的<211>标本的底漆最低为0.5-3.5K。由于还揭示了通过分子动力学模拟引入的双胞胎引入<211>晶体的凝固速度更高，因此双边界的重连角变成扭结位点，可以为晶粒尺寸的刻面生长和晶体尺寸的发展带来优势。并通过增加底层和固化速度在初始固化区域增加0.6至2.4mm/min来增加晶粒尺寸。但是，为了继续如此大的增益大小，有必要将速度降低到0.12至0.3mm/min，直到中间和最终固化阶段。