Study of giant valley splitting at the interface between Si and SiO₂ in SIMOX

First principle calculations

Si has six equivalent minima in the conduction band. They split into 4 dgenerate states and 2 other states at the interface between Si and SiO₂ due to the difference of effective masses in the confinment direction. The lower 2 states are splitted further by submicron eV for a SiO₂ film thermally-grown on a Si film. This is called valley splitting. In 1998, the joint project of a French group and our group discovered that the valley splitting in a SIMOX structure is much bigger (~20 meV) than the usual case.