Demonstration of self-aligned β-Ga2O3δ-doped MOSFETs with current density >550 mA/mm.

We report on the design and fabrication of β -Ga₂O₃ self-aligned lateral MOSFETs by utilizing a heavily doped β -Ga₂O₃ cap layer. The fabrication of the self-aligned device used a combination of in situ Ga etching for damage free gate recess, in situ growth of Al₂O₃ for gate dielectric, and atomic layer deposited Al₂O₃ based sidewall spacers to form highly scaled (<100 nm) source–gate and gate–drain access regions. The fabricated device showed a record high DC drain current density of 560 mA/mm at a drain bias of 5 V. The DC current density was found to be limited by excessive self-heating resulting in premature current saturation in the device. Pulsed I–V measurements of the device showed a record high current density of 895 mA/mm and a high transconductance of 43 mS/mm, thanks to reduced self-heating in the device. The high current densities obtained in this work are promising for the development of high power density devices based on β -Ga₂O₃. [ABSTRACT FROM AUTHOR]