Surface kinetics in AlN growth: A universal model for the control of surface morphology in III-nitrides

• Published in: Journal of crystal growth Vol. 438; pp. 81 - 89
• Main Authors: Bryan, Isaac, Bryan, Zachary, Mita, Seiji, Rice, Anthony, Tweedie, James, Collazo, Ramón, Sitar, Zlatko
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2016
• Subjects: A1. Growth models; A1. Surface kinetics; A3. Metalorganic chemical vapor deposition; Aluminum nitride; B1. Nitrides; Control surfaces; Crystal growth; Epitaxial growth; Misorientation; Morphology; Substrates; Surface kinetics; A1. Growth models; B1. Nitrides; A3. Metalorganic chemical vapor deposition; A1. Surface kinetics
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2015.12.022

AlN epitaxial thin films were grown on both vicinal (0001)-oriented native single crystal AlN substrates and AlN templates grown on vicinal (0001)-oriented sapphire to develop a surface kinetic framework for the control of surface morphology. A Burton, Cabrera, and Frank (BCF) theory-based model is formulated and utilized to understand the dependence of the surface kinetics on the vapor supersaturation, σ, and substrate misorientation angle, α. The surface energy of the Al-polar surface of AlN was experimentally determined using BCF theory to be 149±8meV/Å2. The critical misorientation angle for the onset of step-bunching was determined to be ~0.25° for a growth rate of 500nm/h and temperature of 1250°C. Transitioning from a surface with 2D nuclei to one with bilayer steps required a decrease in σ or an increase in α, whereas the suppression of step-bunching required an increase in σ or a decrease in α. •A kinetic framework for controlling the surface during AlN growth is developed.•The Al-polar surface energy of AlN is experimentally determined using BCF theory.•The transitions between morphologies is controlled by the vapor supersaturation.