Layered growth modelling of epitaxial growth processes for SiC polytypes
Epitaxial growth processes for SiC polytypes in which a SiC substrate
is employed are studied using a layered growth model. The corresponding
phase diagrams of epitaxial growth processes are given.
First-principles calculations are used to determine the parameters in
the layered growth model. The layered growth phase diagrams show that
when the rearrangement of atoms in one surface Si–C bilayer is allowed,
the 3C-SiC structure is formed.
When the rearrangement of atoms in two
surface Si–C bilayers is allowed, the 4H-SiC structure
is formed. When the rearrangement of atoms in more than two surface Si–C
bilayers, excepting the case of five surface Si–C bilayers, is allowed,
the 6H-SiC structure is formed, which is also shown to be the ground
state structure.
When the rearrangement of atoms in five surface Si–C
bilayers is allowed, the 15R-SiC structure is formed. Thus the 3C-SiC
phase would grow epitaxially at low temperature, the 4H-SiC phase would
grow epitaxially at intermediate temperature and the 6H-SiC or 15R-SiC phases would grow epitaxially at higher temperature.
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