【International Papers】A 2.8 kV Breakdown Voltage α-Ga₂O₃ MOSFET with Hybrid Schottky Drain Contact

      Researchers from the Soongsil University of Korea have published a dissertation titled "A 2.8 kV Breakdown Voltage α-Ga₂O₃ MOSFET with Hybrid Schottky Drain Contact " in Micromachines.

Abstract

      Among various polymorphic phases of gallium oxide (Ga₂O₃), α-phase Ga₂O₃ has clear advantages such as its heteroepitaxial growth as well as wide bandgap, which is promising for use in power devices. In this work, we demonstrate α-Ga₂O₃ MOSFETs with hybrid Schottky drain (HSD) contact, comprising both Ohmic and Schottky electrode regions. In comparison with conventional Ohmic drain (OD) contact, a lower on-resistance (R_on) of 2.1 kΩ mm is achieved for variable channel lengths. Physics-based TCAD simulation is performed to validate the turn-on characteristics of the Schottky electrode region and the improved R_on. Electric-field analysis in the off-state is conducted for both the OD and HSD devices. Furthermore, a record breakdown voltage (BV) of 2.8 kV is achieved, which is superior to the 1.7 kV of the compared OD device. Our results show that the proposed HSD contact with a further optimized design can be a promising drain electrode scheme for α-Ga₂O₃ power MOSFETs.

Figure 1. (a) A cross-sectional schematic and (b) top-view scanning electron microscope image of the fabricated α-Ga₂O₃ MOSFET with HSD contact. The blue box represents the drain electrode of OD or HSD. Dashed lines (black) show the region of the focused-ion beam milling for HR-TEM analysis.

Figure 2. HR-TEM images and corresponding EDS elemental mapping images of the (a,b) Schottky and (c,d) Ohmic contact regions.

Paper Link：https://www.mdpi.com/2072-666X/15/1/133