Dependence of substitutional C incorporation on Ge content for Si1−x−yGexCy crystals grown by ultrahigh vacuum chemical vapor deposition

Abstract

Si 1−x−y Ge x C y crystals were grown by ultrahigh vacuum chemical vapor deposition (UHV-CVD) using Si2H6, GeH4, and SiH3CH3 as source gases. Although the total C content in the grown crystals increased with increasing the partial pressure of SiH3CH3 gas, the substitutional C content saturated at a certain value. The maximum substitutional C content was found to change depending on the Ge content. As the Ge content was increased from 13 to 35 at. %, the maximum substitutional C content linearly decreased from 2.0 to 0.8 at. %. These results clearly demonstrate that the existence of Ge atoms prevents the substitutional incorporation of C atoms in Si1−x−yGexCy growth by CVD.

Fabrication technology of SiGe hetero-structures and their properties

“…The crystalline quality of the films is degraded with increasing C fraction and exhibits non-planar morphology, SiC polytype precipitates, and extended defects such as stacking faults and dislocations. Therefore, film growth techniques in which the growth mode is governed not by thermodynamics but kinetics are now widely employed, such as MBE [142,143,169,170], UHV-CVD [171,172], and RTCVD [173,174]. However, it still remains an essential issue in the growth of high quality epitaxial Si 1ÀxÀy Ge x C y films with a substitutional C content higher than 3% and this limits a potential of the films to be applied widely to various kinds of devices [170,175].…”

Modeling and simulation of power trench MOSFET with SiGeC-based channel

“…it is impossible to make the carbon atoms into the substitutional sites completely for the SiGeC system with carbon content more than 1%. under all kinds of processing conditions compatible with Si [7]. That is, the SiGeC epitaxial layer can deteriorate quickly resulting from misfit dislocation, defects and Si-C precipitates when the carbon content is more than 1% [8].…”

Research on SiGeC power diodes with fast and soft recovery

“…Actually, it is impossible to make all the carbon atoms into the substitutional sites for the SiGeC system with carbon content greater than I%~under all kinds of processing conditions compatible with Si [5] [6]. That ist he SiGeC epitaxial layer would be deteriorated quickly due to misfit dislocations~defects and Si-C precipitates when carbon content is more than 1% [7]. Thus~carbon content is strictly limited to be less than 1%.…”