Influences of Process Temperature on a Phase of <scp>Ga<sub>2</sub>O<sub>3</sub></scp> Thin Films Grown by Atomic Layer Deposition on Sapphire
Seung Hyun Lee, Kangmin Lee, Sang Woon Lee, Sang Woon Lee, Sang Woon Lee
Abstract
Influences of process temperature on the phase of Ga 2 O 3 thin films grown by atomic layer deposition (ALD) on a sapphire substrate is investigated. Ga 2 O 3 thin films grown by ALD at a process temperature of 200°C showed an amorphous phase; however, crystalline α‐Ga 2 O 3 film was deposited at the deposition temperatures from 225 to 250°C. Above a process temperature of 300°C, α and β phases coexist in the grown Ga 2 O 3 thin film. Interestingly, β‐Ga 2 O 3 thin film was deposited on the sapphire by an increase of working pressure during Ga 2 O 3 ALD process at the process temperature of 300°C. The bandgap of β‐Ga 2 O 3 thin film was as high as ~5.2 eV. A metal–semiconductor–metal type photodetector using the β‐Ga 2 O 3 thin film exhibited a fast response speed with a short rise time of 1.3 μs for the detection of deep ultraviolet wavelengths.