Enhanced thickness uniformity of large-scale α-Ga2O3 epilayers grown by vertical hot-wall mist chemical vapor deposition. Issue 4 (15th February 2022)

• Record Type: Journal Article
• Authors: Park, Sun-Young; Ha, Minh-Tan; Kim, Kyoung-Ho; Van Lich, Le; Shin, Yun-Ji; Jeong, Seong-Min; Kwon, Se-Hun; Bae, Si-Young
• Is Part Of: Ceramics international. Volume 48:Issue 4(2022)
• Page Start: 5075
• Page End: 5082
• Publication Date: 2022-02-15
• Subjects: Vertical mist CVD -- Ga2O3 -- Large scale -- Thickness uniformity; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.11.045
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Smooth surface morphology and high thickness uniformity heteroepitaxy of corundum-structured ( α- ) gallium oxide (Ga2 O3 ) crystalline thin films on 100-mm diameter c -plane sapphire substrates were successfully demonstrated using vertical hot-wall mist chemical vapor deposition (CVD). The growth rate and surface morphology of the epitaxial layers were numerically and experimentally found to be dependent on the diameter of the precursor-diluted microdroplets approaching the substrate surface. Since the microdroplet is gradually evaporated while traveling through the furnace, the growth variables such as temperature, mist-flow velocity, and substrate position were tuned to obtain a suitable diameter of microdroplets approaching the substrate. In this study, the diameter of the approaching microdroplet was ≈2 μm, which was optimal for the smooth surface (root mean square roughness ≈1 nm) of α -Ga2 O3 epitaxial layers with a growth rate of ≈230 nm/h. Due to the even flow of mist in the vertical furnace, high thickness uniformity of the α -Ga2 O3 epitaxial layer is guaranteed on large-scale substrates, with a standard deviation of thickness as small as 28 nm, paving the way for highly reliable Ga2 O3 -based electric and optoelectronic devices.