The evolution of the surface morphologies of AlN films grown by hydride vapor 

 

phase epitaxy (HYPE) was studied using atomic force microscopy (AFM). Our results 

 

indicate that, after an initial growth time of 10 min, the surface is dominated by 

 

hexagonal-prism-shaped islands. Dislocation mediated surface structures of spiral 

 

hillocks are observed to cover the surface when the growth time extends to 1 h. Upon 

 

further extending the growth time to 3 h, the typical surface morphologies change 

 

and the density of dislocation decreases by one order. We also discuss the 

 

relationship between the diffusion behaviors of adatoms on the crystal surface with 

 

the shape of the terrace edges around dislocations. Explorations into the evolution 

 

of the surface morphology of AlN epitaxial films are crucial for understanding the 

 

origin and subsequent annihilation of dislocations, as well as to promote improved 

 

dislocation reduction techniques for Ill-nitride materials. (C) 2014 Elsevier B.V. 

 

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