Low dislocation density AlN on sapphire prepared by double sputtering and annealing

Abstract

AlN on sapphire with dislocation density of 10 7 cm -2 was prepared by double sputtering and annealing processes.Full width at half maximum values of X-ray rocking curve for ( ) 0002 and ( ) 1012 diffractions of the AlN films were measured to be 10-20 arcsec and 65-82 arcsec, respectively.Dislocations were characterized by plan-view and cross-sectional transmission electron microscopy, and the total dislocation density was estimated as 4.3 10 7 cm -2 .A polarity inversion layer was found between the two sputtered AlN layers, which increased the possibility of blocking dislocations stemming from the AlN/sapphire interface.

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