Study on a novel vertical enhancement-mode Ga2O3 MOSFET with FINFET structure

A novel enhanced mode (E-mode) Ga₂O₃ metal-oxide-semiconductor field-effect transistor (MOSFET) with vertical FINFET structure is proposed and the characteristics of that device are numerically investigated. It is found that the concentration of the source region and the width coupled with the height of the channel mainly effect the on-state characteristics. The metal material of the gate, the oxide material, the oxide thickness, and the epitaxial layer concentration strongly affect the threshold voltage and the output currents. Enabling an E-mode MOSFET device requires a large work function gate metal and an oxide with large dielectric constant. When the output current density of the device increases, the source concentration, the thickness of the epitaxial layer, and the total width of the device need to be expanded. The threshold voltage decreases with the increase of the width of the channel area under the same gate voltage. It is indicated that a set of optimal parameters of a practical vertical enhancement-mode Ga₂O₃ MOSFET requires the epitaxial layer concentration, the channel height of the device, the thickness of the source region, and the oxide thickness of the device should be less than 5×10¹⁶ cm^-3, less than 1.5 μm, between 0.1 μm-0.3 μm and less than 0.08 μm, respectively.