Epitaxy of Si_1%xC_x via ultrahigh-vacuum chemical vapor deposition using Si₂H₆, Si₃H₈, or Si₄H₁₀ as Si precursors

In this study, disilane (Si₂H₆), trisilane (Si₃H₈), and tetrasilane (Si₄H₁₀) were used as Si precursors for the growth of Si₁%_xC_x epilayers, and the growth properties of the layers were compared. The use of a higher-order silane significantly increased the growth rates of the Si₁%_xC_x epilayers at a processing temperature of 650 °C. In addition, a higher growth rate realized by using a higher-order silane promoted an increase in the substitutional carbon concentration in the Si₁%_xC_x epilayers owing to the additional injection of a C-source gas (SiH₃CH₃) and the incorporation of C atoms into substitutional sites. The differences in growth properties between Si precursors were explained on the basis of reaction mechanisms.