Fast Homoepitaxy on (100) β‐Ga 2 O 3 Substrates With Large Grown‐In Offcut

ABSTRACT Crystalline orientation and offcut angle are non‐trivial for low‐symmetry β‐Ga 2 O 3 , where anisotropy impacts bulk and thin film synthesis, material properties, and power device fabrication and performance. Scalable (100)‐oriented β‐Ga 2 O 3 wafers are desirable for electronic devices but are not typically used as substrates due to 10–30x slower epitaxial growth rates compared to other orientations. Here we report molecular beam epitaxy (MBE) growth rates equal to the fast growth direction by using (100) Ga 2 O 3 wafers with large grown‐in offcuts. Offcuts up to 13.4° (β‐angle minus 90°), with vertically aligned (001) planes, are directly grown by Edge‐defined Film‐fed Growth (EFG) of 2D ribbons with rotated seed crystals, avoiding material loss from crystal boule offcut methods while maintaining high crystalline quality. Chemical‐mechanical polishing produces epitaxy‐ready substrates, and step flow growth is observed across offcuts. We measure an unintentional n‐type doping density < 2 × 10 15 cm −3 , one of the lowest values reported for MBE. Planar Schottky barrier diodes on these epilayers without edge termination have an on/off ratio ∼10 5 and an average breakdown field of 1.56 MV/cm, comparable to or exceeding similar devices fabricated on other orientations. Overall, these results illustrate the importance of orientation and offcut, validating the use of the scalable (100)‐oriented β‐Ga 2 O 3 wafers.