Interplay of vacancies, hydrogen, and electrical compensation in irradiated and annealed n-type β-Ga2O3

Positron annihilation spectroscopy, Fourier transform-infrared absorption spectroscopy, and secondary ion mass spectrometry have been used to study the behavior of gallium vacancy-related defects and hydrogen in deuterium (D) implanted and subsequently annealed beta-Ga2O3 single crystals. The data suggest the implantation generates a plethora of V-Ga-related species, including V-Ga1- and V-Ga2-type defects. The latter's contribution to the positron signal was enhanced after an anneal at 300 degrees C, which is driven by the passivation of Vib Ga by hydrogen as seen from infrared measurements. Subsequent annealing near 600 degrees C returns the positron signal to levels similar to those in the as-received samples, which suggests that split V-Ga-like defects are still present in the sample. The almost complete removal of the V(Ga)(ib-)2D vibrational line, the appearance of new weak O-D lines in the same spectral region, and the lack of D outdiffusion from the samples suggest that the 600 degrees C anneal promotes the formation of either D-containing, IR-inactive complexes or defect complexes between V-Ga(ib)-2D and other implantation-induced defects. The degree of electrical compensation is found to be governed by the interactions between the Ga vacancies and hydrogen.Published under an exclusive license by AIP Publishing.

Automated summary

The study found that hydrogen passivates V-Ga defects in beta-Ga2O3 single crystals during annealing, and the 600 degrees Celsius annealing promotes the formation of complexes containing D or other defects.