Recent progress in deep-depletion diamond metal–oxide–semiconductor field-effect transistors

Diamond has been explored to develop prototype field-effect transistors (FETs). At present, various architectures that are suited to high temperature and high-radiation environments are still under investigation for power electronics applications. Recently, the deep-depletion diamond metal–oxide–semiconductor FET (D3MOSFET) concept has been introduced and demonstrated to be a good candidate for designing efficient diamond MOSFETs. In this paper, a general introduction to the concept of deep depletion is given. The key issues concerning the design and fabrication of this kind of diamond MOSFET are then described and discussed in terms of quasi static performance (the 'on' and 'off' states). A demonstration of the working regimes of a fabricated normally-on D3MOSFET is described, which reached a critical field of at least 5.4 MV cm⁻¹ at a drain–source bias of −175 V, without electric field relaxation structures. The minimum on-state resistance was measured and found to be R _ON,S = 50 mΩ cm² at 250 ^∘C. Finally, the D3MOSFET is contextualized as part of a global research effort to develop diamond power FETs. Some of the main challenges regarding the fabrication of competitive D3MOSFETs and, more generally, diamond power devices are discussed. (topical review)