摘要
应用微波光电导衰减仪（μ-PCD）测得了铸造多晶硅硅锭沿生长方向少子寿命的分布图。结果显示：距离硅锭底部4～5cm以及顶部约2cm的范围内均存在一个少子寿命值过低的区域，而硅锭中间区域的少子寿命值较高且分布均匀。通过将样品在200℃下热处理10min，根据处理前后少子寿命值的变化，获得了间隙铁浓度沿硅锭方向的一维线性分布曲线。从曲线中可以发现铁在硅锭两端浓度较高，这与硅锭冷却过程中铁从坩埚向硅锭底部发生的固相扩散以及铁的分凝特性有关。另外通过傅立叶变换红外光谱仪（FTIR）测试发现间隙氧浓度在硅锭底部较高，呈现从硅锭底部向顶部逐渐降低的趋势。研究结果表明硅锭中存在的高浓度的氧、铁等杂质为影响其少子寿命值的关键因素。
The minority carrier lifetime（τ） scan mapping along the multicrystalline ingot was obtained by means of Microwave Photo Conductive Decay （μ - PCD）. The lifetime measurements exhibit a width of the degraded regions of the order of 4-5 centimeters at the bottom and about 2cm at the top of the ingot, while a large uniform with high lifetime zone exist in the central position. By measuring the τ before and after sample annealing at 200℃ for l0 minutes, the interstitial iron concentration can be evaluated. The results show that there is a strong increase towards both the top and the bottom of the ingot, and this is attributed to the solid-state diffusion from the crucible after crystallization and the segregation into the molten phase. The profile of interstitial oxygen concentration was investigated by FTIR, the results show that the concentration of oxygen decreases from the bottom to the top of the ingot, which is dominated mainly by the segregation mechanism. The high concentration of impurities such as iron and oxygen, which can induce electrically active recombination centers, is believed to be responsible for the lifetime reduction in the two sides of the ingot.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2007年第2期151-154,共4页
Acta Energiae Solaris Sinica
基金
国家科技攻关计划(2004BA410A02)
教育部留学人员基金
国家杰出青年基金
关键词
铸造多晶硅
少子寿命
间隙铁
氧
multicrystalline silicon
minority carrier lifetime
interstitial iron
oxygen
