Surface reaction of CH₃SiH₃ on Ge(100) and Si(100)

Surface reaction of CH₃SiH₃ on the Ge(100) and Si(100) surfaces was investigated in the low-temperature region of 400-500 °C using ultraclean hot-wall low-pressure chemical vapor deposition (CVD) systems, where CH₃SiH₃ was supplied at a partial pressure of 18 Pa for 0-240 min. On Ge(100), the concentrations of Si and C deposited at 400 °C and 450 °C saturate to the value corresponding to the single atomic layer, but those at 500 °C increase continuously with exposure time. Nevertheless, at all the temperatures studied, the concentration of deposited Si is nearly the same as that of deposited C. In the case of SiH₄ exposure at 450 °C at partial pressures of 6 and 60 Pa, it was found that the Ge atoms segregate on the top surface at the early stage of Si deposition. By comparing these results, it is considered that the adsorption of CH₃SiH₃ suppresses the Ge segregation. On Si(100), the C deposition by CH₃SiH₃ has a similar tendency to that on Ge(100), but the initial deposition efficiency is lower than that on Ge(100). Moreover, the FTIR/RAS Si-hydride peak shifts to the lower wave numbers after CH₃SiH₃ exposure. These results suggest that CH₃SiH₃ is adsorbed without breaking the Si-C bond on Ge(100) and Si(100) at 400-500 °C.