Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-09-09 |
| Journal | Advanced Materials |
| Authors | Jianbo Liang, Ayaka Kobayashi, Yasuo Shimizu, Yutaka Ohno, SeongâWoo Kim |
| Institutions | Saga University, Osaka City University |
| Citations | 96 |
Abstract
Section titled âAbstractâAbstract The direct integration of gallium nitride (GaN) and diamond holds much promise for highâpower devices. However, it is a big challenge to grow GaN on diamond due to the large lattice and thermalâexpansion coefficient mismatch between GaN and diamond. In this work, the fabrication of a GaN/diamond heterointerface is successfully achieved by a surface activated bonding (SAB) method at room temperature. A small compressive stress exists in the GaN/diamond heterointerface, which is significantly smaller than that of the GaNâonâdiamond structure with a transition layer formed by crystal growth. A 5.3 nmâthick intermediate layer composed of amorphous carbon and diamond is formed at the asâbonded heterointerface. Ga and N atoms are distributed in the intermediate layer by diffusion during the bonding process. Both the thickness and the sp 2 âbonded carbon ratio of the intermediate layer decrease as the annealing temperature increases, which indicates that the amorphous carbon is directly converted into diamond after annealing. The diamond of the intermediate layer acts as a seed crystal. After annealing at 1000 °C, the thickness of the intermediate layer is decreased to approximately 1.5 nm, where lattice fringes of the diamond (220) plane are observed.