Effect of Al thickness on the Al induced low temperature poly-si film crystallization process

Abstract

In our previous study, we fabricates large grain low temperature poly-crystalline silicon film by aluminum induced crystallization (AIC) method. The fabrication process is to deposite aluminum layer on top of the a-Si:H film deposited by plasma enhanced chemical vapor deposition (PECVD) [1]. In this paper, we discussed more about the effect of different aluminum thickness of the AIC process. Five kinds of specimens with different aluminum thickness of, 10, 20, 40, 80, and 160 nm, respectively; are fabricated and tested. The annealing temperature is set at 350°C and 30 min in the annealing stage. The crystallinity of the annealed silicon film is discussed in this paper. XRD and Raman spectra analysis are used to identify the crystallinity of specimens made under different aluminum thicknesses. Raman results show that a-Si film will be crystallized if the Al film thickness is over 40 nm aluminum thickness. The crystallinity volume fraction calculated is about 45∼90%. The I–V characteristic is tested to see the magnitude of leakage current of poly silicon film made in our study.