Threading dislocation density comparison between GaN grown on the patterned and conventional sapphire substrate by high resolution X-ray diffraction

• Published in: Science China. Physics, mechanics & astronomy mechanics & astronomy, 2010-03, Vol.53 (3), p.465-468
• Main Authors: Zhang, YuChao, Xing, ZhiGang, Ma, ZiGuang, Chen, Yao, Ding, GuoJian, Xu, PeiQiang, Dong, ChenMing, Chen, Hong, Le, XiaoYun
• Format: Article
• Language: English
• Subjects: Astronomy; Classical and Continuum Physics; Diffraction patterns; Dislocation density; Edge dislocations; High resolution; Metalorganic chemical vapor deposition; Observations and Techniques; Organic chemicals; Organic chemistry; Physics; Physics and Astronomy; Raman spectra; Research Paper; Sapphire; Substrates; Threading dislocations; X-ray diffraction
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-010-0148-4

GaN epifilms are grown on the patterned sapphire substrates (PSS) (0001) and the conventional sapphire substrates (CSS) (0001) by metal-organic chemical vapor deposition (MOCVD) using a novel two-step growth. High resolution X-ray diffraction (HR-XRD) is used to investigate the threading dislocation (TD) density of the GaN epifilms. The TD density is calculated from the ω-scans full width at half maximum (FWHM) results of HR-XRD. The edge dislocation destiny of GaN grown on the PSS is 2.7×10 8 cm −2 , which is less than on the CSS. This is confirmed by the results of atomic force microscopy (AFM) measurement. The lower TD destiny indicates that the crystalline quality of the GaN epifilms grown on the PSS is improved compared to GaN epifilms grown on the CSS. The residual strains of GaN grown on the PSS and CSS are compared by Raman Scattering spectra. It is clearly seen that the residual strain in the GaN grown on PSS is lower than on the CSS.