Heteroepitaxial Growth of Single-Crystalline β-Ga<sub>2</sub>O<sub>3</sub> on GaN/Al<sub>2</sub>O<sub>3</sub> Using MOCVD
Dahee Seo, Sunjae Kim, Hyeong-Yun Kim, Dae‐Woo Jeon, Ji-Hyeon Park, Wan Sik Hwang
Abstract
The formation of n -Ga 2 O 3 / p -GaN heterojunctions has been studied intensively due to the lack of p -Ga 2 O 3 . Metalorganic chemical vapor deposition (MOCVD) is known to provide a high-quality heterojunction of n -Ga 2 O 3 / p -GaN compared to thermal oxidation, sputtering, or pulsed-laser deposition (PLD). In this work, single-crystalline β-Ga 2 O 3 of {−201} is grown on a GaN (001)/Al 2 O 3 substrate using MOCVD. An abrupt heterojunction without a noticeable interfacial layer is observed between β-Ga 2 O 3 and GaN. However, due to the lattice mismatch between β-Ga 2 O 3 (−201) and GaN (001), grain boundaries and grain defects originating from the Ga 2 O 3 /GaN interface continue in β-Ga 2 O 3 in a diagonal direction. The epitaxial nature of the grown β-Ga 2 O 3 on the GaN (001)/Al 2 O 3 substrate causes the nanorod-shaped morphology in the growth direction of β-Ga 2 O 3 . This work marks a step toward the formation of a high-quality heterojunction of Ga 2 O 3 /GaN, which would serve as an essential building block for various devices, including optoelectronics and power electronics.