HREM study of stacking faults in GaN layers grown over sapphiresubstrate

Abstract

Epitaxial GaN layers grown on sapphire contain a very large density of defects(threading dislocations, stacking faults, inversion domain boundaries, .). Amongthese defects, we have performed the analysis of the basal stacking faults byhigh resolution transmission electron microscopy. Two faults, I1 and I2,were identified. The formation of the I1 fault is based on theclimb-dissociation process of the (1/3)⟨11-20⟩ or of the[0001] perfect dislocations whereas the I2 fault is due to the shear of thestructure leading to a partial dislocation loop.