Evaluation of physical and electrical properties of CoSi₂ thin films on (100)Si grown by pulsed laser deposition

Abstract

Laser physical vapour deposition (LPVD) has been used to deposit thin CoSi₂ films on (100) silicon at different substrate temperatures ranging from room temperature to 600°C. Silicide films were deposited by ablating a solid target of CoSi₂ in vacuum with a pulsed KrF excimer laser. Particulate-free silicide thin films were characterized by X-ray diffraction, Rutherford backscattering, and analytical and high-resolution transmission electron microscopy. We have found that films deposited at 200°C and below are amorphous; films deposited at 400°C are polycrystalline; and films deposited at 600°C are (001) textured. Resistivity of these films has been measured as a function of temperature. This plot for CoSi₂ exemplifies a typical resistivity behaviour for metallic compounds. The room temperature resistivity has been found to be about 15μΩ cm with a residual resistivity of about 4 μΩ cm for these films. A theoretically based Bloch-Gruneisen model has been applied to analyse the nature of such a plot. These results suggest that LPVD technique could be used for the deposition of stoichiometric low resistivity silicide thin films using lower thermal budgets. The correlation between microstructure and electrical properties of these films is discussed.