Self-aligned patterning on β-Ga2O3 substrates via backside-exposure photolithography

beta-Ga2O3 has not been patterned using backside-exposure lithography, despite its high potential applications in future power electronics and its transparency to conventional lithography light sources. Here, a patterned metal on a beta-Ga2O3 substrate surface was used as an embedded photomask to demonstrate the applicability of backside-exposure lithography to beta-Ga2O3 substrates. Self-aligned photoresist patterning, lift-off, and etching processes were demonstrated for an AZ5214E photoresist in both the positive and negative processing modes. The findings suggest that backside-exposure photolithography is a promising fabrication approach for future beta-Ga2O3-based devices.