Diffusivity of Si in the 3C-SiC Buffer Layer on Si(100) by X-ray Photoelectron Spectroscopy

A void free 3C-SiC film grown on Si(100) can be achieved by low pressure chemical vapor deposition using the modified four-step method. The diffusion step plays an important role to enhance the quality of the 3C-SiC buffer layer on Si(100). X-ray photoelectron spectroscopy was used to characterize the bonding characteristics of the 3C-SiC buffer layer of about 10 nm thick. The Si-C bonds are partially formed on the as-carburized Si(100) before the diffusion step. The ratio of C-C to Si-C bonds on the as-carburized Si(100) is about 7:3, which can be lowered to about 1:9 after the diffusion step at 1350 oC for 5 min or at 1300 oC for 7 min. According to XPS data and Fick's second law, the diffusivity of Si across the 3C-SiC interlayer are determined to be 2.2×10 -16 cm 2 /s and 3.13×10 -16 cm 2 /s at 1300°C and 1350°C, respectively. The derived activation energy is 1.6 eV for the diffusion of Si atoms in the 3C-SiC buffer layer.