Si1−xGex growth using Si3H8 by low temperature chemical vapor deposition

Low temperature epitaxial growth of group-IV alloys is a key process step to realize the advanced Si-based devices. In order to keep high growth rate below 600 °C, trisilane (Si3H8) was used for their growth as an alternative Si precursor gas. Then, we compared the use of Si3H8 versus SiH4 for Si1−xGex growth in H2 and N2 as carrier gas by low temperature chemical vapor deposition. By using Si3H8 and controlling GeH4 flow rate, Si1−xGex growth with high growth rate and wide range of Ge concentration has been achieved compared to SiH4-based process. The growth rate and Ge concentration in Si1−xGex with Si3H8 grown at 600 °C ranged from 11 to 74 nm/min and from 0 to 40%, respectively. The obtained growth rates with Si3H8 are between 1.5 and 6 times higher than for SiH4 at a given growth condition. Si3H8-based in-situ B- and C-doped Si1−xGex growth with high growth rate was also demonstrated.