In this paper, we analyze the electrical behavior and the deep levels present in nitrogen-implanted gallium oxide Schottky barrier diodes annealed at increasing temperature from 800 °C to 1200 °C. In gallium oxide, nitrogen implantation is used in order to achieve controlled isolation of parts of the final device, and its stability and performance is therefore of high importance.

The high temperature annealing carried out after implantation causes a reduction in the leakage current flowing in the structure, confirming the feasibility of nitrogen implantation as isolation procedure and the annealing of the defects caused by the implantation process.

Repeated current-voltage measurements show the presence of an electron trapping process in the structure. The involved deep levels were investigated by means of isothermal transient spectroscopy tests, and both current and capacitance were used to monitor the trapping level in the devices. A model was developed to explain the full set of collected data on all the annealing temperatures, based on thermionic injection of electrons into an intermediate deep level and on charge injection into the space charge region.

In this paper we analyze the conduction properties, charge trapping and threshold voltage instability of normally-on β-Ga₂O₃ lateral MOSFETs for high power applications by means of threshold voltage transients. We found that a positive bias applied to the gate induces a rightward shift in the threshold voltage, caused by the trapping of electrons at border traps close to the semiconductor-dielectric interface.

The amount of trapped charge was investigated by an innovative fast-CV experimental setup and was found to follow a logarithmic kinetic in time, modeled by a generalization of the inhibition model that takes into account the effect of columbic repulsion in stress conditions.