Carrier capture kinetics, deep levels, and isolation properties of <b> <i>β</i> </b>-Ga2O3 Schottky-barrier diodes damaged by nitrogen implantation
Carlo De Santi, Manuel Fregolent, Matteo Buffolo, Man Hoi Wong, Masataka Higashiwaki, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
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.