Fabrication of poly-Si prepared by excimer laser recrystallization - effect of both side nucleation on secondary grain growth

摘要

In this paper, we investigate the effect of heat sink on the crystal growth, especially secondary grain growth of polycrystalline Si (poly-Si) prepared by excimer laser irradiatetion to Si(heat sink)/a-Si(50nm)/quartz structure from quartz side. Difference of Raman peak shift or FWHM between the poly-Si surface and the poly-Si/quartz interface with the heat sink is smaller than that without the heat sink. This result indicates that the difference of internal stress or crystal defects between the surface and the interface with the heat sink is smaller than that without the heat sink. XRD intensity of poly-Si with the heat sink is larger than that without the heat sink. It is considered that heat sink enhances the crystal growth. From the SEM results, the dominant crystal growth mechanism for 400mJ/cm{sup}2 and 100shot without the heat sink and with the heat sink are microcrystal-growth from the super cooled liquid and secondary grain growth, respectively. From TEM observation, the stress relaxation occurs by forming the stacking faults in the poly-Si grain with the heat sink. We discuss these results assuming that the nucleation occurs not only from the a-Si/quartz interface but also from the surface of a-Si.