SPECTROSCOPIC ELLIPSOMETRY APPLIED TO THE CHARACTERIZATION OF GaN AND AlGaN/GaN HETERO-STRUCTURES

摘要

UV/Visible spectroscopic ellipsometry is applied to the characterization of GaN epilayer and AlGaN/GaN hetero-structures deposited on sapphire substrate. From these analysis the optical indices of the different materials is deduced and precise structural information are extracted. The different layer thickness are precisely determined and surface roughness problems can be detected. From the measured band gap the composition of AlGaN ternary compound can estimated.