Thermal stability improvement of Si1− y C y layers by SiO2 cap layers

Abstract: We studied on the thermal stability improvement of Si1− y C y against high temperature annealing by using SiO2 cap layers. The Si1− y C y films with a carbon concentration of 1.0% were grown at 620 °C by a gas source MBE. From XRD measurements, the layer with a carbon concentration of 0.79% formed in the Si1− y C y films without SiO2 cap layers after annealing at 900 °C and it indicated the segregation of carbon atoms. The 100-nm SiO2 cap layers effectively prevented the segregation of carbon atoms when the Si1− y C y film thickness was less than its critical thickness. X-ray reciprocal lattice space maps around (115) reciprocal lattice points supported these phenomena, showing that the SiO2 cap layer improved the thermal stability of Si1− y C y films against annealing at 900 °C. [Copyright &y& Elsevier]