(Invited) Β-Ga₂O₃ Traps: Materials to Devices

Abstract

Traps in β-Ga 2 O 3 keep devices, such as power transistors, photodetectors, and diodes, from working ideally. This manifests itself as short-term (ns to ms time scales) to longer term (day to week long) instabilities in terminal characteristics including dynamic on-resistance and threshold voltage and as increased leakage currents that degrade breakdown voltage and noise equivalent power. Using both conventional deep level transient and optical spectroscopies (DLTS/DLOS) and direct, quantitative defect spectroscopy on transistors namely constant drain current DLTS (CI D -DLTS), the trap energies and concentrations in test structures and metal-semiconductor field effect transistors (MESFETs) are quantified and compared with the instabilities in the MESFET threshold voltage and dynamic on-resistance are correlated showing which traps matter in these MESFETs. A critical step in defect spectroscopy is to identify the sources of defects to enable strategies to eliminate the defects or bring them down to tolerable levels. Our group and the community have made great strides in beginning to identify the defects throughout the bandgap. Using high energy proton and neutron irradiation to create native defects and controlled studies with Fe, the two primary defects that cause threshold voltage instability in MESFETs will be discussed along with mitigation strategies.