Presentation Information
[11a-PA6-15]MOCVD-GaN growth using MBE-GaN template on ScAlMgO4 substrates
〇Gentatsuro Hata1, Sigeharu Kawabata1, Md. Earul Islam1, Takashi Fujii1,2, Trang Nakamoto1, Tuguo Hukuda2, Syoichi Onda3, Ryuichi Sugie1, Tutomu Araki1 (1.Ritsumeikan Univ., 2.Fukuda Crystal Lab., 3.GaNVaL LLC)
Keywords:
semiconductor,SAM,GaN
ScAlMgO4 (SAM) single crystals are attractive substrates for GaN epitaxial growth because they can be easily cleaved parallel to the c-plane, enabling substrate removal. We have previously demonstrated direct GaN epitaxial growth on SAM substrates by RF-MBE. To achieve thicker GaN layers, MOCVD growth on MBE-GaN/SAM templates has been investigated. In our previous study, partial delamination of GaN films was observed after MOCVD growth.In this study, the relationship between the growth conditions of MBE-GaN templates and the delamination behavior of MOCVD-GaN films was investigated. Approximately 500-nm-thick GaN templates were grown on 50-mm-diameter SAM substrates by RF-MBE, followed by GaN growth using MOCVD. Delamination was observed in all MOCVD-grown films, and the delaminated area increased with increasing XRD FWHM of the MBE-GaN/SAM templates. To clarify the origin of the delamination, MBE-GaN/SAM samples were annealed at 1020°C for 120 min in a nitrogen atmosphere before MOCVD growth. No cracks or delamination were observed on the MBE-GaN surface after annealing. TEM observations of the delaminated films and discussions on the delamination mechanism will also be presented.