Analysis of Strain and Defect in GaN on Commercial Patterned-Sapphire Substrates with Raman Spectrometer

• Main Authors: Shang-Hsuan Wu, 吳尚軒
• Other Authors: 管傑雄
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/8x6745

碩士 === 國立臺灣大學 === 光電工程學研究所 === 105 === Using Metal-Organic Chemical Vapor Deposition to grow gallium nitride thin film on a patterned sapphire substrate can reduce the threading dislocation density and increase the crystal quality, and reduce the defect density (defect density).Most of literature were metioned that using XRD to measure lattice constant to compare the relationship between stress and strain,and using EPD to get dislocation density.Because of the difference of vibration mode of phonon,we can measure different Raman shift. We can analyze the difference of stress from Raman shift.Therefore we supposed that we can use μ-Raman to replace XRD and EPD.So we do experiment to prove it.We use same recipe to grow GaN with different thickness on commercial patterned sapphire substrate which have single period microstructure; however , we have different thickness GaN on the sapphire substrate, but we found that with the change of the thickness of the GaN, gallium nitride crystal growth will present two very different faces,and are subject to different stress, which can affect the efficiency of the use made of the subsequent electronic components.In the final stage, this paper will discuss the stress and defect density with different methods and use Transmission electron microscope to observe the phenomenon of dislocation . We find out that the measurement by Raman is more accurate than XRD.Using Raman will be a trand in the future . Thus improving efficiency of electronic devices which was grown on the gallium nitride thin film.