Effect of off-cut angle of hydrogen-terminated diamond(111) substrate on the quality of AlN towards high-density AlN/diamond(111) interface hole channel

Single-crystal AlN/diamond heterojunction with high-density interface hole channel is successfully obtained by metal-organic vapor phase epitaxy. The AlN layer is epitaxially grown on hydrogen-terminated (H-) diamond(111) substrate. The thermal treatment of diamond substrate just before AlN growth under hydrogen and ammonia mixture environment at 1250 degrees C leads to surface sheet hole density as high as similar to 1.0 x 10(14) cm(-2) without structural reconstruction of diamond surface. In addition, the use of smaller off-cut angle (0.20 +/- 0.25 degrees) H-diamond(111) substrate combined with this treatment enables to obtain single-crystal epitaxial AlN layer, which simultaneously acts as passivation of the surface hole channel with such a high density. The AlN/H-diamond(111) heterojunction reveals type-II staggered energy band configuration with valence band offset of similar to 2.0 eV, which is suitable for the fabrication of p-channel field-effect transistor using AlN-gate-insulator/diamond heterojunction. These results are promising for the development of AlN/diamond hybrid power electronic devices. Published by AIP Publishing.