Characterization of beta-Ga2O3 homoepitaxial films and MOSFETs grown by MOCVD at high growth rates

The ultra-wide bandgap semiconductor gallium oxide (Ga2O3) offers substantial promise to significantly advance power electronic devices as a result of its high breakdown electric field and maturing substrate technology. A key remaining challenge is the ability to grow electronic-grade epitaxial layers at rates consistent with 20-40 mu m thick drift regions needed for 20 kV and above technologies. This work reports on extensive characterization of epitaxial layers grown in a novel metalorganic chemical vapor deposition tool that permits growth rates of 1.0-4.0 mu m h(-1). Specifically, optical, structural and electrical properties of epilayers grown at similar to 1 mu m h(-1) are reported, including employment in an operating MOSFET. The films demonstrate relatively smooth surfaces with a high degree of structural order, limited point defectivity (N-d - N-a 5 x 10(15) cm(-3)) and an optical bandgap of 4.50 eV. Further, when employed in a MOSFET test structure with an n(+) doped channel, a record high mobility for a transistor structure with a doped channel of 170 cm(2) V-1 s(-1) was measured via the Hall technique at room temperature. This work reports for the first time a beta-Ga2O3 MOSFET grown using Agnitron Technology's high growth rate MOCVD homoepitaxial process. These results clearly establish a significant improvement in epilayer quality at growth rates that can support future high voltage power device technologies.