Deep level study of chlorine-based dry etched β − Ga2O3

Chlorine-based gases are used for the reactive ion etching (RIE) of β − Ga 2 O 3. However, the effects of Cl-plasma on the electronic properties of β − Ga 2 O 3 are not known. In order to shed light on this topic, we carried out an experimental and theoretical study on β − Ga 2 O 3 epilayers treated with Cl 2 / Ar or BCl 3 / Ar plasma. We found four traps in the 0.2–0.8 eV energy range below the conduction band edge ( E C). Two of these, located at E C-0.24 eV and E C-0.28 eV, arise only when the epilayers are treated with BCl 3 / Ar. While the involvement of Cl in their microscopic structure is not discarded, the possibility that these two levels might have an intrinsic nature seems more plausible. Our findings might explain the reported effects on the Schottky barrier diodes of β − Ga 2 O 3 when RIE is employed during processing.