Effects of post-deposition annealing temperatures in argon ambient on structural, optical, and electrical characteristics of RF magnetron sputtered gallium oxide films

Different post-deposition annealing temperatures were carried out in argon ambient to investigate the corresponding effects onto structural, morphological, optical, and electrical characteristics of RF magnetron sputtered gallium oxide (Ga2O3) films. Cubic phase of g-Ga2O3 was transformed to mixed phases of cubic and monoclinic phases of I3-Ga2O3 as the temperature was increased from 400 to 800 degrees C before became fully I3-Ga2O3 phases at 1000 degrees C. Oxygen vacancies and oxygen interstitials were formed, generating deep energy levels in band gap of the Ga2O3 films. Findings revealed the acquisition of the highest current density in the Ga2O3 film annealed at 400 degrees C as a consequence of the highest density (J) of dislocation and oxygen vacancies in the film. Nonetheless, the formation of a thicker interfacial layer and location of oxygen vacancies in the film annealed at 1000 degrees C have caused minute increase in the J surpassing that of 800 degrees C at a gate voltage greater than 15 V.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Different annealing temperatures were used to investigate the effects on structural, morphological, optical, and electrical characteristics of RF magnetron sputtered gallium oxide (Ga2O3) films. The phase of the film transformed from g-Ga2O3 to mixed phases of cubic and monoclinic I3-Ga2O3 with increasing temperature, and fully converted to I3-Ga2O3 at 1000°C. Oxygen vacancies and interstitials were formed, creating deep energy levels in the band gap of the Ga2O3 film. The highest current density was observed in the film annealed at 400°C, attributed to the highest density of dislocation and oxygen vacancies in the film. However, a thicker interfacial layer and the location of oxygen vacancies at 1000°C annealing caused a slight increase in current density compared to 800°C at gate voltages greater than 15V.