Metal-organic chemical vapor deposition of epsilon-Ga2O3 thin film using N2O as a precursor

As a novel wide bandgap semiconductor, epsilon phase Ga2O3 is characterized by an extremely high polarization coefficient and could be applied in different kinds of piezoelectric or electronic devices. However, to date, the growth technologies of epsilon-Ga2O3 have been so limited that high quality epsilon-Ga2O3 is still unavailable. In this work, epsilon-Ga2O3 thin films were grown on c-plane sapphire substrates by metal-organic chemical vapor deposition (MOCVD) using a two-step method. The effect of using N2O as an oxygen precursor for the epitaxial growth of epsilon-Ga2O3 is investigated. The phase purity and growth mode of Ga2O3 thin films are investigated for samples prepared under different conditions. Phase transition takes place depending on the VI/III ratio, which is explained by the interplay of thermodynamic and kinetic effects. At a growth temperature of 600 degrees C, the full width at half maximum (FWHM) of the epsilon-Ga2O3 (004) plane rocking curve is as low as 0.20 degrees, demonstrating that N2O could be a potential precursor for the MOCVD growth of epsilon-Ga2O3.