Trench-type inversion-channel diamond MOSFET enabled by thermochemical etching based on C solid solution into Ni

This is the authors' abstract. We don't add key points for this paper.

Trench-type inversion-channel diamond MOSFETs have ultimate potential as low-loss power devices, and their practical realization is highly anticipated. The fabrication of this device requires the formation of diamond trenches with {111} sidewalls because inversion layers can only be formed on diamond {111} surfaces. However, conventional etching techniques such as reactive ion etching (RIE) face difficulties in forming such structures. In this study, we achieved the formation of diamond trenches with {111} sidewalls in a doped diamond multilayer structure by employing our thermochemical etching technique. Furthermore, by applying our inversion-layer formation technique, we realized the formation of an inversion-channel on the trench sidewalls. As a result, we fabricated a trench-type inversion-channel diamond MOSFET and demonstrated its operation for the first time. The fabricated device showed clear FET characteristics and normally-off behavior at both room temperature and 300 °C. These results establish an important foundation for the realization of ultra-low-loss diamond power devices.