Wet Chemical and Plasma Etching of Ga2 O 3 ( Gd2 O 3 )

Abstract

Gallium arsenide metal oxide semiconductor field effect transistors (GaAs MOSFETs) were successfully demonstrated with a specially formulated gallium oxide/gadolinium oxide as the gate dielectric material. For the fabrication of MOSFETs, dry and wet etching of has been investigated. The content of in the oxide is dependent on the deposition conditions and can vary from 10 to approximately 44%. The etching characteristics of the film is affected by the content of Gd. An HCl based wet etch shows smooth surface morphologies of and would not attack the underlying GaAs. The etch rate of is linearly proportional to the concentration of HCl. Furthermore, the etching was determined to be a reaction‐limited process. For dry etching, the rates for both and based discharges are very low due to the incorporation of Gd and the lack of etch selectivity to the GaAs substrate.