Large-Area In-Situ Oxide, GaN Interlayer-Based Vertical Trench MOSFET (OG-FET)

We present a large-area in-situ oxide, GaN interlayer-based vertical trench MOSFET (OG-FET) with a metal organic chemical vapor deposition regrown 10-nm unintentional-doped-GaN interlayer as the channel and 50-nm in-situ Al
₂
O
₃
as the gate dielectric. The threshold voltage of the device on bulk GaN substrate was 1 V measured at I
_on
/I
_off
= 10
⁷
. The OG-FET with an area scaled to 0.2 mm
²
demonstrated a breakdown voltage (V
_BR
) of 320 V and an on-state resistance (R
_on
) of 3.8 Ω (specific on-state resistance: R
_on,sp
= 7.6 m Ω· cm
²
). For the single unit cell OG-FET from the same sample, VBR was as high as 700 V (measured at V
_GS
= -10 V), corresponding to a breakdown electric field of 1.4 MV/cm andRon,sp of 0.98 mΩ · cm
²
. On our control sample, which was grown on sapphire substrate, a 1-A current was measured as well. These results show the potential of the OG-FET in power conversion applications.