Trap states and hydrogenation of implanted Si in semi-insulating Ga2O3(Fe)

The electrical properties and deep trap spectra of semi-insulating Ga2O3(Fe) implanted with Si ions and subsequently annealed at 1000 °C were investigated. A significant discrepancy was observed between the measured shallow donor concentration profile and the profile predicted by Stopping Power and Range of Ions in Matter simulations, indicating substantial compensation. Deep level transient spectroscopy revealed the presence of deep acceptors at Ec −0.5 eV with a concentration of ∼10¹⁷ cm−³, insufficient to fully account for the observed compensation. Photocapacitance spectroscopy identified additional deep acceptors with optical ionization thresholds near 2 and 2.8–3.1 eV, tentatively attributed to gallium vacancy-related defects. However, the combined concentration of these deep acceptors still fell short of explaining the observed donor deactivation, suggesting the formation of electrically neutral Si-vacancy complexes. Furthermore, the properties of Ga2O3 (Fe) implanted with Si and subjected to hydrogen plasma treatment at 330 °C were also examined. This material exhibited high resistivity with the Fermi level pinned near Ec –0.3 eV, similar to common radiation defects in proton-implanted Ga2O3. A prominent deep center near Ec −0.6 eV, consistent with the known E1 electron trap attributed to Si-H complexes, was also observed. These results highlight the challenges associated with Si implantation and activation in Ga2O3 and suggest that hydrogen plasma treatment, while effective for Ga-implanted Ga2O3 is less suitable for Si-implanted material due to the formation of compensating Si-H complexes.