Growth of N-doped β-Ga₂O₃ homoepitaxial layers by halide vapor phase epitaxy using NH₃ as the doping source

N-doped β-Ga 2 O 3 (010) homoepitaxial layers were grown by halide vapor phase epitaxy using NH 3 as the doping source. The N concentration, [N], was controlled by varying the input partial pressure of NH 3 ( P 0 NH 3 ) while keeping the partial pressure of O 2 ( P 0 O 2 ) constant. The [N] value was approximately proportional to the control parameter R N = P 0 NH 3 /( P 0 NH 3 + 2 P 0 O 2 ), and increased from about 3.1 × 10 18 to 1.3 × 10 21 cm −3 as R N was raised. At [N] ~ 10 21 cm −3 , surface roughening, cracking, and degradation of the crystallographic orientation occurred, whereas high crystallinity was maintained for [N] up to the mid-10 19 cm −3 range.