Growth mechanism of α-Ga_2O_3 on a sapphire substrate by mist chemical vapor deposition using acetylacetonated gallium source solutions

摘要

α-Ga_2O_3 is a metastable phase of gallium oxide (Ga_2O_3) and is important for application in solar-blind region optoelectronic devices. High-quality α-Ga_2O_3 thin films can be grown by mist chemical vapor deposition (mist-CVD). We systematically investigate the growth mechanism of α-Ga_2O_3 by mist-CVD using acetylacetonated Ga source solutions. We propose a growth mechanism of α-Ga_2O_3 in mist-CVD in which acetylacetonate ligands anchor to surface hydroxyls and Ga-O bonds are formed by a ligand exchange mechanism. The origin of oxygen atoms and impurity concentration profiles in grown α-Ga_2O_3 thin films are examined by secondary ion mass spectroscopy.