低温铝诱导形成纳米硅的特性研究

Study on the properties of nanocrystalline silicon formed by aluminum-induced crystallization at low temperature

采用玻璃/氢化非晶硅(a-Si∶H)/铝结构,在低温(≤350℃)下,应用铝诱导晶化法(AIC),形成了纳米硅(nc-Si).利用X射线衍射(XRD)光谱、拉曼(Raman)光谱和紫外可见近红外光谱(UV-Vis-NIR),研究了退火升温时间对a-Si∶H薄膜的结构及其光学特性的影响.结果表明,随着退火升温时间的增加,a-Si∶H膜的晶化率Xc增加而硅晶粒尺寸基本不变,光吸收系数α增加.这主要是由于铝和氢化非晶硅膜之间的氧化层很薄以及退火升温导致Al-Si之间的互扩散增强,使硅的成核密度很高和扩散到a-Si∶H膜中的铝浓度较高造成的.

Nanocrystalline silicon （nc-Si） is formed by aluminum-induced crystallization （AIC） of amorphous silicon at low temperatures （≤350℃） with a stack of glass/a-Si：H/A1. The structure and optical properties of the AIC sample are analyzed by X-ray diffraction, Raman and UV-Vis-NIR spectrum. The results shown that with increasing annealing ramp-up time the crystalline volume fraction （Xc） and the optical absorption coefficient （a） increase, the si grain size （about 8 nm） remains unchanged. For the oxide film between the A1 and the a-Si： H layer is thin, which leads to a stronger interdiffusion between A1 and Si, the nucleation density of silicon is considerably high. Besides, the A1 atoms diffused into a-Si ： H film during AIC process and this enhanced the optical absorption of a-Si：H film.