非晶硅薄膜的准分子激光晶化研究

利用Kr准分子激光器晶化非晶硅薄膜, 研究了不同的激光能量密度和脉冲次数对非晶硅薄膜晶化效果的影响.利用X 射线衍射(XRD)和扫描电子显微镜(SEM)对晶化前后的样品的物相结构和表面形貌进行了表征和分析.实验结果表明, 在激光频率为1 Hz 的条件下, 能量密度约为180 mJ/cm2时,准分子激光退火处理实现了薄膜由非晶结构向多晶结构的转变;当大于晶化阈值180 mJ/cm2小于能量密度230 mJ/cm2时, 随着激光能量密度增大, 薄膜晶化效果越来越好;激光能量密度为230 mJ/cm2时, 晶化效果最好、晶粒尺寸最大, 约60 nm, 并且此时薄膜沿Si(111)面择优生长;脉冲次数50 次以后对晶化的影响不大.

Crystallization of amorphous Si films by excimer laser annealing

Amorphous silicon(a:Si) films were annealed by KrF excimer laser to realize the influence of different power density and different pulse counts. The analysis of a:Si thin film microstructure and surface morphology was conducted using X-ray diffractometer(XRD) and scanning electron microscope (SEM). In the range of 1 Hz, the results show that the polycrystalline silicon structure has been achieved from amorphous silicon by excimer laser annealing when the energy density reaches about 180 mJ/cm2. When the energy density is from the energy density threshold 180 mJ/cm2 to the energy density 230 mJ/cm2, the crystallization effect gets better with the increase of the energy density. The effect of crystallization is best and the gain size is the biggest while the energy density is 230 mJ/cm2. The maximum average size of the grain reaches 60 nm and the polycrystalline silicon film grows preferentially along the crystallographic(111) orientation. The influence of pulse counts are not remarkable if the pulse counts are over 50 times.