Characteristics of GaN/Si(1 1 1) epitaxy grown using Al_0.1Ga_0.9N/AlN composite nucleation layers having different thicknesses of AlN

摘要

We have studied the effects of Al_0.1Ga_0.9N(150 nm)/AlN composite nucleation layers (CNLs) having different thicknesses of AlN ranging from 20 to 41 nm on the growth characteristics of GaN/Si(1 1 1) epitaxy. The surface morphology of the GaN epitaxial layers which were grown on Al_0.1Ga_0.9N(150 nm)/AlN CNLs showed that the number of thermal etch pits and cracks were abruptly decreased with the increase of AlN thickness from 20 to 35 nm. However, the morphology of GaN epitaxy which was grown on Al_0.1Ga_0.9N(150 nm)/AlN CNL having AlN of thickness 41 nm above 35 nm showed that the number of etch pits increased again.