Synthesis of h-BN/diamond heterojunctions and its electrical characteristics

Abstract

Conductive channel on the surface of hydrogen terminated diamond with two-dimensional h-BN passivation exhibits high hole mobility. However, the current h-BN passivated diamond mainly uses the method of mechanical peeling, which cannot achieve a large-size conductive channel and is difficult to meet the actual application requirements. In this study, the effect of classical transfer h-BN on the conductive channel on the surface of hydrogen terminated diamond is studied. High-quality single crystal diamond is epitaxially grown by microwave chemical vapor deposition (MPCVD) and the hydrogen terminated diamond is obtained by surface hydrogenation treatment. H-BN/H-diamond heterojunctions with different layers of h-BN are prepared by wetting transfer, and the characteristics of channel carrier transport are systematically studied. The results show that the channel conductivity is significantly enhanced after h-BN transfer, and with the increase of h-BN thickness, the enhancement effect of channel conductivity tends to be stable. The transfer of multilayer h-BN can increase the carrier density on the surface of hydrogen terminated diamond by nearly 2 times, and the square resistance is reduced to 50%. The current results show that the h-BN/H-diamond heterojunction may have a transfer doping effect, resulting in a significant increase in carrier density. With the increase of the channel carrier density, the channel mobility on the surface of the h-BN passivated diamond remains stable. The H-BN absorbs on the surface of the diamond, so that the negative charge originally on the surface of the hydrogen termination moves to the surface of h-BN, and the distance of action increases, weakening the coupling of the negative charge of the hole with the negative charge of the dielectric layer in the conductive channel of the hydrogen terminated diamond, which makes the mobility stable.