Large-Area In-Situ Oxide, GaN Interlayer-Based Vertical Trench MOSFET (OG-FET)
We present a large-area <italic>in-situ</italic> 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 <italic>in-situ</italic> Al<sub>2</sub>O<sub>3</sub> as the gate dielectric. The threshold voltage of the device on bulk GaN substrate was 1 V measured at <inline-formula> <tex-math notation="LaTeX">$\text{I}_\mathrm {on}/\text{I}_\mathrm {off}= 10^{7}$ </tex-math></inline-formula>. The OG-FET with an area scaled to 0.2 mm<sup>2</sup> demonstrated a breakdown voltage (<inline-formula> <tex-math notation="LaTeX">$\text{V}_\mathrm {BR}$ </tex-math></inline-formula>) of 320 V and an on-state resistance (<inline-formula> <tex-math notation="LaTeX">$\text{R}_\mathrm {on}$ </tex-math></inline-formula>) of <inline-formula> <tex-math notation="LaTeX">$3.8~\Omega $ </tex-math></inline-formula> (specific on-state resistance: <inline-formula> <tex-math notation="LaTeX">$\text{R}_\mathrm {on,sp}= 7.6\,\,\text{m}\Omega \,\,\cdot $ </tex-math></inline-formula> cm<sup>2</sup>). For the single unit cell OG-FET from the same sample, <inline-formula> <tex-math notation="LaTeX">$\text{V}_\mathrm {BR}$ </tex-math></inline-formula> was as high as 700 V (measured at <inline-formula> <tex-math notation="LaTeX">$\text{V}_\mathrm {GS}=-10$ </tex-math></inline-formula> V), corresponding to a breakdown electric field of 1.4 MV/cm and <inline-formula> <tex-math notation="LaTeX">$\text{R}_\mathrm {on,sp}$ </tex-math></inline-formula> of 0.98 <inline-formula> <tex-math notation="LaTeX">$\text{m}\Omega ~\cdot $ </tex-math></inline-formula> cm<sup>2</sup>. 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.