固体纳秒激光器应用于非晶硅薄膜结晶的研究

发布时间：2018-09-19 12:37

【摘要】：多晶硅薄膜比非晶硅薄膜具有更高的电子迁移率,在器件中表现出更优良的性能,脉冲激光结晶非晶硅薄膜制备多晶硅薄膜的方法具有热积存小、对衬底影响小、成本低等优点。使用532 nm固体纳秒激光器进行了非晶硅薄膜激光结晶实验,为了解决直接使用高斯光束结晶时因光斑能量分布带来的结晶效果不均匀,首先基于光束整型系统将圆形的高斯光束整型成为线性平顶光束,而后研究单脉冲能量密度、脉冲个数、非晶硅薄膜厚度对结晶效果的影响。结果表明,线性平顶光束用于非晶硅薄膜结晶具有更好的均匀性,对于100 nm非晶硅薄膜,随着能量密度的增加,晶粒逐渐变大,直到表面出现热损伤,最大晶粒尺寸约为1μm×500 nm。随着脉冲个数的增加,表面粗糙度有减小的趋势,观察到的最小粗糙度约为2.38 nm。对于20nm超薄非晶硅薄膜,只有当能量密度位于134 mJ/cm~2和167 mJ/cm~2之间、脉冲个数大于或等于八个时才能观察到明显的结晶效果。
[Abstract]:Polycrystalline silicon films have higher electron mobility than amorphous silicon thin films and exhibit better performance in devices. The method of preparing polycrystalline silicon thin films by pulsed laser crystallization has smaller thermal accumulation and less influence on substrates. Low cost and other advantages. The laser crystallization experiment of amorphous silicon thin film was carried out by using 532nm solid-state nanosecond laser. In order to solve the uneven crystallization effect caused by the energy distribution of the spot when Gao Si beam was used directly, Firstly, the circular Gao Si beam is transformed into a linear flat-top beam based on the beam integral system, and then the effects of single pulse energy density, number of pulses and thickness of amorphous silicon film on the crystallization effect are studied. The results show that the linear flat-top beam has better homogeneity for amorphous silicon film crystallization. For 100 nm amorphous silicon film, with the increase of energy density, the grain size increases gradually, until the thermal damage occurs on the surface, the maximum grain size is about 1 渭 m 脳 500 nm.. With the number of pulses increasing, the surface roughness tends to decrease, and the observed minimum roughness is about 2.38 nm.. For 20nm ultrathin amorphous silicon thin films, only when the energy density is between 134 mJ/cm~2 and 167 mJ/cm~2 and the number of pulses is greater than or equal to eight can the effect of crystallization be observed.
【作者单位】：中国科学院半导体研究所;中国科学院微电子研究所;
【基金】：国家自然科学基金面上项目(No.61376083) 中国科学院院装备研制项目资助
【分类号】：TN249;TN304.12

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