Demonstration of self-aligned β-Ga2O3 δ-doped MOSFETs with current density >550 mA/mm

We report on the design and fabrication of beta-Ga2O3 self-aligned lateral MOSFETs by utilizing a heavily doped beta-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 beta-Ga2O3.

Automated summary

We presented the design and fabrication of beta-Ga2O3 self-aligned lateral MOSFETs with a heavily doped beta-Ga2O3 cap layer. The fabricated device achieved a record high DC drain current density of 560 mA/mm at 5V drain bias, although the current density was limited by excessive self-heating. However, pulsed I-V measurements showed a record high current density of 895 mA/mm and a high transconductance of 43 mS/mm, indicating reduced self-heating in the device. These findings are promising for the development of high power density devices based on beta-Ga2O3.