GaN 스트라이프 꼭대기 위의 AlGaN 어레이 미세구조의 선택적 결정 성장

Abstract

Department of Electronic Materials Engineering, Korea Maritime and Ocean University, Busan 49112, Korea(Received September 14, 2015)(Revised October 6, 2015)(Accepted October 12, 2015)Abstract The growth and characterization of micro sized AlGaN array structures selectively grown by metal organicchemical vapor deposition (MOCVD) on GaN stripes are reported. The shape of the AlGaN array structures depends onthe size of exposed area for selective growth. The AlGaN array structures grown selectively on relatively large exposedarea have regular shapes resembling those of the GaN stripes on the substrate, while samples selectively grown onrelatively small exposed area have irregular shapes. The phonon frequency of the AlGaN array structures increases withincreasing Al composition in the AlGaN structure. However, at relatively high Al composition (x = 0.28 in this research),the phonon frequency decreases slightly from the expected value not only because of large tensile strain associated withlarge differences between the lattice constants of the AlGaN structure and underlying GaN stripes but also changes ofcrystal facet direction during the selective growth.Key wordsGaN, AlGaN, GaN stripe, Selective growth, AlGaN structure, MOCVD, Strain, Raman spectroscopy