Nucleation and growth of TiSi2 thin films deposited on glass by atmospheric pressure chemical vapor deposition

Abstract

Titanium silicide (TiSi2) thin films were prepared on glass substrate by atmospheric pressure chemical vapor deposition using SiH4 and TiCl4 as the precursors. The phase structure of the thin films was identified by x-ray diffractometry. The surface morphology and thickness of the thin films were observed by field emission scannig electron microscopy and the sheet resistance of the thin films was measured using the four point probe method. The results show that the TiSi2 thin films are formed in a face-centered orthorhombic structure. Due to the influence of the amorphous glass substrate, an amorphous layer is initially formed on the substrate and the TiSi2 crystalline phase grows on top of it. As the thickness and content of TiSi2 crystalline phase increase with deposition time, the resistivity of the thin film decreases. Besides, the growth rate and thus the size of TiSi2 crystalline phase increase as the deposition temperature increases. The stack density decreases when the deposition temperature increases above 700°C because the rapid growth at the higher temperatures causes more irregular shape of crystalline particles. The maximal stack density of the crystalline phase and thus the minimum resistivity of the thin films are obtained at the deposition temperature of 700°C. The expressions of the stack density of crystalline phase and the resistivity of the thin films as functions of the deposition conditions are theoretically deduced which are well consistent with the experimental results.