높은 전자 이동도의 바륨 스테네이트 박막 증착 최적화와 전자 이동도 극대화 열처리 공정 개발

Optimization of High Electron Mobility Barium Stannate Thin Film Deposition and Development of Thermal Treatment for Electron Mobility Maximizatio

Using pulsed laser deposition, the synthesis of epitaxial La-doped BaSnO₃ (LBSO) thin films was optimized by controlling plasma plume dynamics with parameters such as pressure, laser energy, and target-substrate distance. This allowed precise tuning of the Ba/Sn ratio, ultimately leading to LBSO films with high electron mobility and carrier density. During post-growth hydrogen annealing, precise control of oxygen partial pressure and temperature simultaneously increased electron density and mobility, achieving a room-temperature mobility of 130 cm V⁻ s⁻ . While hydrogen annealing could potentially reduce mobility due to charged oxygen vacancies, careful regulation of oxygen partial pressure increased the electron mobility significantly. This improvement was primarily attributed to oxygen-vacancy-assisted recovery in the ionic lattice, which induces reduced threading dislocation density and crystal mosaicity. Furthermore, this research provided a comprehensive guideline for defect engineering through thermal treatment. While reducing conditions improved crystallinity and mobility, they also induced Sn vacancy formation, which strongly trapped free electrons. Therefore, slightly Sn-excess LBSO films were found to be optimal for maximizing room-temperature mobility after hydrogen annealing. This study utilized LBSO thin films as a model system to explore defect control during synthesis and post-treatment, investigating the correlation between defect engineering and electronic properties. The findings highlight that thermodynamic defect control strategies during film deposition and annealing can offer new pathways to enhance room-temperature electron mobility in epitaxial oxide thin films.