Thin silicon films synthesis by AIC on ONO coated metal foils

Thin film crystalline silicon solar cells on flexible metallic substrates are being considered to be potential for low cost production. In the present investigation, metallic substrates (MS) coated with dielectric diffusion barrier layer (BL) of ONO (SiO2/SiN/SiO2) have been used for the fabrication of polycrystalline silicon (pc-Si) thin films using aluminium induced crystallisation (AIC) for the first time. The crystallographic quality of pc-Si layers synthesised by AIC has been studied using Raman and UV reflection spectroscopy. Similarly, grain size and defect distribution were characterised using electron backscattered diffraction (EBSD) analysis. The AIC grown films showed a symmetric peak around 519–520 cm−1 with an average grain size of 8.1 μm. The thermal stability of the diffusion barrier has been evaluated by annealing the structure, MS/BL/pc-Si, at higher temperatures with subsequent chemical analysis of AIC grown pc-Si template. The potential impurities are identified to be Fe and Ni on a limited area. These results open the potential of fabrication of large grain silicon seed layer on flexible substrates for thin film solar cells technology.