The crystallinity analysis of poly-Si film with different deposition sequences of aluminum and a-Si layers by aluminum induced crystallization method

In our study, we fabricated polycrystalline silicon film by aluminum induced crystallization method. Two different sequences of aluminum (Al) and amorphous silicon (a-Si) layers were deposited on glass substrates. The a-Si film was deposited by plasma enhanced chemical vapor deposition (PECVD). The Al film was deposited by sputtering. The specimens were then annealed under 450°C of annealing temperature for 7 hours. Al-etching process was performed on these annealed specimens to remove the Al content in the specimens. Optical microscopy (OM), Raman spectroscopy and Hall measurements were performed in order to analyze their crystallinity and electrical properties. Results shows that the mobility of poly-Si film for the specimens with the glass/Al(75 nm)/(Oxidation layer)/a-Si(85 nm) is not very good although the crystallinity is very good due to the discontinuous crystal growth of the poly-Si film. However, both the mobility and crystallinity are improved as the thicknesses of the a-Si/Al film thickness increase to 400/400 nm.