Effects of glass substrate coated by different-content buffer layer on the quality of poly-Si thin films

Abstract

In this work, polycrystalline silicon (poly-Si) thin films were fabricated by aluminum induced crystallization (AIC) technique. SiNx, deposited as a function of NH3/SiH4 ratio, and AZO (Al-doped ZnO) films on glass were used as a buffer layer between glass and Si film. The effect of buffer layer content on the crystallinity of poly-Si thin films was studied by Raman analysis which shows that fully crystallization without stress was achieved for all samples. Moreover, the preferred crystalline orientation and crystallite size of films were deduced by X-ray diffraction (XRD) analysis. The preferred orientation is <100> as independent from the buffer layer content while the crystallite sizes increase up to 48.5 nm by increasing the amount of SiH4. The electrical properties of the films were carried out by four point probe and current–voltage (I–V) analysis. Both techniques demonstrated that the resistivity of the SiNx-based samples is around 0.1 Ωcm. The grain size analysis was accomplished by electron back scattering diffraction (EBSD) measurements. The grain size up to 25 µm was achieved as observed from EBSD images. The results show that the fabrication parameters of SiNx and AZO buffer layers have the great effects on the crystallography of poly-Si films.