COMPOSITE GRATING MEDIUM LAYER APPLICABLE TO GROUP III-V SUBSTRATE AND PREPARATION METHOD THEREOF

摘要

A composite grating medium layer (2) applicable to a group III-V substrate and a preparation method thereof. The composite grating medium layer (2) comprises: an AlxY2-xO3 interface passivation layer (23) formed on a group III-V substrate (1); and a high dielectric constant insulation layer (24) formed on the AlxY2-xO3 interface passivation layer (23); wherein 1.2≤x≤1.9. By adjusting a ratio of Al/Y in the AlxY2-xO3 interface passivation layer (23), the composite grating medium layer (2) changes an averaged coordination number of an atom in the AlxY2-xO3 interface passivation layer (23), reduces an interface state density and boundary trap density of the group III-V substrate (1), and increases a MOS channel mobility rate. By incorporating the AlxY2-xO3 interface passivation layer (23) and the high dielectric constant insulation layer (24), the embodiments of the invention reduce a leakage current, and enhance quality and reliability of a MOS capacitor of the group III-V substrate (1).