First-principles study of the electronic properties of Ge dangling bonds at (100)Si_(1_x)Ge_x/SiO_2 interfaces

摘要

First-principles calculations of the electronic properties of (100)Si_(1-x)Ge_x/SiO_2 structures, with a Ge dangling bond at the interface, are reported. It is found that the defect level associated with this dangling bond approaches the valence band edge of the Si_(1-x)Ge-x substrate as the Si concentration is reduced, mainly due to the narrowing of the energy bandgap of the alloy. These results suggest that these dangling bonds likely behave as acceptor-type defects at Ge-rich (100)Si_(1-x)Ge_x interfaces.