Diamond Field Effect Transistors With MoO3 Gate Dielectric

We report the first attempt of the diamond MOSFETs with MoO
₃
dielectric directly deposited on H-diamond surface preserving atmospheric-adsorbate-induced 2DHG. The transistors with 4-μm gate show a transconductance of 29 mS/mm and an ON-resistance of 75.25 Ω · mm at |VGS - VTH| = 2.2 V, respectively. The effective mobility is extracted to be 108 cm
₂
/(Vs) from the relationship between the ON-resistance and |VGS - VTH|. The relatively high transconductance among the reported diamond MOSFETs with the same gate length could be attributed to the quite low ON-resistance. The evaluated high mobility indicates good interface characteristics between diamond and MoO
₃
. However, the saturation drain current is limited at 33 mA/mm by the forward gate breakdown at VGS of around -2 V.