Strain behavior of epitaxial Si_{1 - x}C_x films on silicon substrates during dry oxidation

The effects of the oxidation of Si_{1 - x}C_x films (x = 0.0125) on Si (100) substrates were evaluated. Epitaxial Si _{1 - x}C_x (x = 0.0125) films were deposited by ultrahigh-vacuum chemical vapor deposition at 600 °C. Oxidation at 800 °C and 900 °C under an O₂ ambient in a tube furnace resulted in a decrease in substitutional C concentration, due to the formation of interstitial carbon or β-SiC precipitation. Transmission electron microscopy analyses indicated that the formation of β-SiC on the Si _{1 - x}C_x layer occurred when the oxidation temperature exceeded 900 °C. This indicates that relaxation of compressive stress in the depth direction occurred as the result of the formation of β-SiC. No evidence was found for the segregation of carbon at the top of the Si _{1 - x}C_x layers during the oxidation of the Si _{1 - x}C_x layer unlike the Ge pile up that occurs during the oxidation of Si_{1 - x}Ge_x layers.