Effect of unintentional nitrogen incorporation on n-type doping of β-Ga2O3 grown by molecular beam epitaxy

Abstract

The effect of unintentional nitrogen incorporation on n-type doping of β-Ga₂O₃ films grown by plasma-assisted molecular beam epitaxy was demonstrated. Nitrogen atoms, at a concentration as high as 2 × 10¹⁹ cm⁻³, were confirmed to originate from the decomposition of a pyrolytic boron nitride (PBN) crucible in the plasma source. These atoms acted as acceptors in β-Ga₂O₃ and severely compensate Si donors, thereby hindering the generation of n-type β-Ga₂O₃. Instead, a quartz (SiO₂) crucible free of nitrogen atoms could overcome this problem, and led to generation of n-type β-Ga₂O₃ with a tunable electron concentration of 5.0 × 10¹⁶ to 2.6 × 10¹⁹ cm⁻³.