Characterization of low temperature epitaxial Si and Si 1− yC y films grown by hot wire cell method

Abstract

The hot wire (HW) cell method was applied to grow epitaxial Si and strained Si 1− y C y films at very low substrate temperature. The epitaxial Si films were successfully obtained on Si(001) at a substrate temperature ( T sub) of 150–250 °C and a SiH 4 pressure of 0.015–0.03 Torr by using only SiH 4. The structure of the Si films became polycrystalline or microcrystalline either at T sub of over 300 °C or the pressure of over 0.06 Torr. Carbon was introduced to the films by using C 2H 2 gas and the epitaxial growth of Si 1− y C y at low T sub was also possible by using the hydrogen dilution. The concentration of substitutional C was 0.9%, when the ratio [C 2H 2/SiH 4] was 0.04. Furthermore, X-ray reciprocal lattice space mapping, indicated the pseudomorphic growth of Si 1− y C y alloy on Si. The thermostability of strained Si 1− y C y films grown by HW cell method was also investigated and the concentration of the substitutional C in the films decreased by annealing at over 800 °C.