Textured magnesium titanate as gate oxide for GaN-based metal-oxide-semiconductor capacitor

We demonstrate the first high-permittivity ceramic oxide for use as the gate oxide of the GaN-based metal-oxide-semiconductor (MOS) capacitor. An ilmenite magnesium titanate (MgTiO₃) thin film prepared by sputtering was studied. When oxygen was introduced during sputtering, the preferred orientation changed from spinel Mg₂TiO₄ (111) to ilmenite MgTiO₃ (003). The X-ray diffractometry Î-2Î andφ-scans were performed to identify the preferred films. Possible epitaxial relationships at the Mg₂TiO₄ (111)/GaN (001) and MgTiO₃ (003)/GaN (001) interfaces were proposed. Finally, the electrical properties of the Al/MgTiO₃ (003)/GaN (001)/Al MOS capacitor were presented.