Improvement of GaAs metal–semiconductor field-effect transistor drain–source breakdown voltage by oxide surface passivation grown by atomic layer deposition

Oxide surface passivation grown by atomic layer deposition (ALD) has been applied to GaAs metal–semiconductor field-effect transistors (MESFETs). The breakdown characteristic of a MESFET is greatly improved by both Al2O3 and HfO2 passivation. Three-terminal transistor breakdown voltage is improved to a maximum level of 20V with Al2O3 passivation from 11V without any surface passivation. With the removal of native oxide and passivation on GaAs surface at drain–gate (D–G) and source–gate (S–G) spacings, the device breakdown characteristics are significantly improved.