The Fermi level at the Ga oxide/GaAs interface has been unpinned by rf plasma cleaning the GaAs surface in H2and N2. Following plasma cleaning, a Ga oxide film is reactively electron beam deposited onto the substrate. Metal‐oxide‐semiconductor (MOS) capacitors fabricated on these structures show good high‐frequency capacitance‐voltage characteristics. This indicates that the density of interface states has been reduced to ∼1011eV−1 cm−2. The MOS capacitors are found to be stable in air after several months.