Single-crystal α-GaN grown on a α-Ga2O3 template layer

Publisher Website
Google Scholar
Abstract
The mechanism for growth of single-crystal GaN on oxidized AlAs ( AlO x ) formed on a Si(111) substrate by metalorganic chemical vapor deposition has been studied. Cross-sectional transmission electron microscopy (XTEM) indicates that the grown GaN is single-crystal α-GaN in spite of the fact that the AlO x on which the GaN is grown is found to contain predominantly polycrystal γ- Al 2 O 3 . Reflection high-energy electron diffraction(RHEED) shows that oriented crystallized α- Ga 2 O 3 is formed between AlO x and the GaAs cap layer during the oxidation process. The α- Ga 2 O 3 acts as a growth template and results in the crystalline orientation of α-GaN on polycrystal γ- Al 2 O 3 . Further support for this template is derived from energy dispersive x-ray spectroscopy that shows the existence of Ga atoms on AlO x . Combined XTEM/RHEED analysis suggests that α-GaN is oriented in the growth direction as [0001] α-GaN ∥[0001] α-Ga 2 O 3 ∥[111] Si and the in-plane direction as [2 11 ¯ 0] α-GaN ∥[11_00] α-Ga 2 O 3 ∥[011_] Si , which can be understood by considering the misfit in the in-plane atomic separation at each interface.