Enhancement-Mode Current Aperture Vertical Ga2O3 MOSFETs

Ga ₂ O ₃ is attractive for power electronics owing to its wide bandgap of 4.5 eV and the availability of economical melt-grown native substrates. Normally-off vertical power switches are highly sought-after since they allow for superior field termination and current drive at the device level while ensuring fail-safe operation and simplified designs at the system level. Capitalizing on ion-implantation technologies for donor (Si) [1] and deep acceptor (N) [2] doping of Ga ₂ O ₃ , we have demonstrated depletion-mode (D-mode) vertical Ga ₂ O ₃ MOSFETs [3] in which Si-ion (Si ⁺ ) implanted top n ⁺⁺ source contacts are electrically isolated from the bottom drain contact by a N-ion (N ⁺⁺ ) implanted current blocking layer (CBL) except at an aperture bounded by CBLs through which drain current (ID) is conducted. The CBL also serves as a back-barrier for a top-gated lateral channel defined by another Si ⁺ implantation step. Based on this manufacturable all-ion-implanted structure, this paper presents accumulation-mode normally-off vertical Ga ₂ O ₃ MOSFETs by appropriately designing the channel doping to control the threshold voltage (VT) without requiring fundamental process modifications.