Micromachines, Volume 12, Issue 4
April 2021 - 120 articles
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Cover Story: The Si substrate has attracted significant interest owing to its lower cost and easy integration with electronic devices. However, when the GaN layer is directly grown on the Si substrate, the Si surface easily reacts with NH3 to form the SiNx that prohibits GaN growth. Furthermore, the large lattice mismatch (~17%) between GaN and Si (111) causes a high dislocation density. Finally, the difference in thermal expansion coefficients (~56%) introduces large tensile stress in the GaN layer, which causes the wafer bowing and crack generation. Therefore, we demonstrate that AlN layers prepared with NH3 growth interruption improve the crystalline quality and strain relaxation in GaN-based LEDs grown on Si substrates. View this paper.