Radiation Damage in the Ultra-Wide Bandgap Semiconductor Ga ₂ O ₃

Abstract

We present a review of the published experimental and simulation radiation damage results in Ga 2 O 3 . All of the polytypes of Ga 2 O 3 are expected to show similar radiation resistance as GaN and SiC, considering their average bond strengths. However, this is not enough to explain the orders of magnitude difference of the relative resistance to radiation damage of these materials compared to GaAs and dynamic annealing of defects is much more effective in Ga 2 O 3 . It is important to examine the effect of all types of radiation, given that Ga 2 O 3 devices will potentially be deployed both in space and terrestrial applications. Octahedral gallium monovacancies are the main defects produced under most radiation conditions because of the larger cross-section for interaction compared to oxygen vacancies. Proton irradiation introduces two main paramagnetic defects in Ga 2 O 3 , which are stable at room temperature. Charge carrier removal can be explained by Fermi-level pinning far from the conduction band minimum due to gallium interstitials (Ga i ), vacancies (V Ga ), and antisites (Ga O ). One of the most important parameters to establish is the carrier removal rate for each type of radiation, since this directly impacts the current in devices such as transistors or rectifiers. When compared to the displacement damage predicted by the Stopping and Range of Ions in Matter(SRIM) code, the carrier removal rates are generally much lower and take into account the electrical nature of the defects created. With few experimental or simulation studies on single event effects (SEE) in Ga 2 O 3 , it is apparent that while other wide bandgap semiconductors like SiC and GaN are robust against displacement damage and total ionizing dose, they display significant vulnerability to single event effects at high Linear Energy Transfer (LET) and at much lower biases than expected. We have analyzed the transient response of β -Ga 2 O 3 rectifiers to heavy-ion strikes via TCAD simulations. Using field metal rings improves the breakdown voltage and biasing those rings can help control the breakdown voltage. Such biased rings help in the removal of the charge deposited by the ion strike.