激光烧蚀制备掺铒纳米硅晶薄膜形貌研究

Morphology of Er-Doped Nanocrystalline Silicon Films Fabricated by Pulsed Laser Ablation

采用XeCl准分子激光器交替烧蚀单晶硅靶和铒靶, 通过调整辐照两靶的激光脉冲个数比来控制掺铒浓度, 在2×10^-4 Pa真空下沉积制备了掺铒非晶硅薄膜, 经900～1200 ℃热退火实现纳米晶化. 扫描电子显微镜图像显示, 铒掺杂影响着薄膜的表面形貌, 与不掺铒情况相比, 可以得到晶粒尺寸分布更均匀的薄膜, 并且晶化温度更低. 对于一个固定掺铒浓度的样品, 随着退火温度的增加, 薄膜由晶粒结构转化为迷津结构.

Both the single crystalline Si and Er targets were ablated alternately by XeC1 excimer laser to fabricate Er-doped amorphous Si films in the vacuum chamber at the base pressure of 2 × 10^-4 Pa, and the concentration of Er-doping can be controlled through laser pulse ratio on both Si and Er targets. The Erdoped nanocrystalline Si （nc-Si） films were obtained via annealing as-deposited samples from 900 to 1200℃. The scanning electron microscope measurements indicate that more uniform nc-Si films and lower crystallinity temperature can be achieved through Er-doping comparing to un-doped Si samples, moreover, Erdoping can control the morphology of the nc-Si films. For certain Er-doped Si sample annealed from 900 to 1200 ℃, with increasing annealing temperature the crystalline structure in transformed into mazing structure.