First quasi-vertical gallium nitride trench MOSFET on 6-inch silicon

Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland claims the first gallium nitride (GaN) quasi-vertical trench gate metal-oxidesemiconductor field-effect transistors (MOSFETs) on 6-inch silicon (Si) substrates with 645V off-state breakdown [Chao Liu et al, IEEE Electron Device Letters, vol39, p71, 2018]. The researchers hope that combining compact verticalstructure GaN MOSFETs with silicon substrates will reduce costs for the emerging power electronics technology. Up to now, vertical GaN power devices have usually been produced on ultra-expensive bulk or free-standing GaN substrates, since reducing threading dislocations is imperative for low current leakage and for avoiding breakdown in the off-state. Threading dislocations arise from the large lattice and thermal expansion mismatch between silicon and GaN.