β-Ga2O3 MOSFETs on highly uniform 2-in. unintentionally doped vertical Bridgman substrates

Beta-phase gallium oxide (β-Ga2O3) is a promising ultra-wide-bandgap (UWBG) semiconductor for next-generation high-power electronics. A critical challenge for commercialization is validating the material quality and uniformity of large-area substrates. In this work, the material quality of a 2-in. unintentionally doped (UID) β-Ga2O3 substrate grown by the vertical Bridgman method is evaluated by analyzing the performance uniformity of metal-oxide-semiconductor field-effect transistors as test structures fabricated on a Si-doped channel layer grown by metal-organic chemical vapor deposition. The high quality and homogeneity of the substrate material was confirmed by the uniform statistical distribution of device parameters across the wafer. Fabricated devices exhibited standard deviations of just 7.32 mA/mm for maximum current density, 3.92 V threshold voltage, and 0.88 mS/mm for peak transconductance, indicating a highly uniform epitaxial layer and channel. Mitigation of the silicon (Si) peak at the substrate-epitaxy interface was highly effective, removing the peak in 99% of devices that were tested via capacitance-voltage testing. The high yield and consistent electrical characteristics validate that the vertical Bridgman substrate technology produces a mature and uniform material platform suitable for scaling up β-Ga2O3 power electronics.