Carrier capture kinetics, deep levels, and isolation properties of β -Ga2O3 Schottky-barrier diodes damaged by nitrogen implantation

Abstract

In this paper, we analyze the stability of the performance of β-Ga2O3 Schottky barrier diodes (SBDs) damaged by nitrogen implantation, based on electrical characterization and deep-level spectroscopy. We demonstrate that N-implanted SBDs show a high level of isolation, which can be further improved by electron trapping promoted by current flow and temperature. Charge trapping leads to a shift in the current–voltage curve to more positive bias, a positive effect lasting for hundreds of seconds at room temperature and fully recovered only after 200 s even at 350 K. This charge trapping process takes place in the depletion region of the Schottky diode, in a defect located 0.72 eV below the conduction band, possibly related to gallium vacancies. A model for explaining the trapping kinetics and processes is proposed, based on differential rate equations, highlighting two capture processes: charge injection from the n-type Ga2O3 into the space charge region and thermionic emission from the anode metal to the deep level.