Comparative study of radiation damage in GaN and InGaN by 400 keV Au implantation

Abstract

In x Ga 1− x N layers on sapphire with x=0 and x=0.1 were implanted with 380/400 keV Au ions. Implantation and subsequent damage analysis by Rutherford backscattering spectrometry with 1.4 MeV He ions backscattered under 170° were performed at 15 K without temperature change of the samples. At this temperature thermal effects can be neglected, which allows us to study the primary defect production. In In 0.1Ga 0.9N no difference is found between the Ga and In defect profiles. The defect concentration in the maximum of the distribution increases linearly with the ion fluence which can be explained by direct impact amorphisation and the growth of amorphous zones once they have formed. In GaN even at the low temperature of 15 K, recombination of defects within the collision cascades dominates. This causes two intermediate plateaus in the defect concentration versus the ion fluence before amorphous zones nucleate and final amorphisation of the layer is reached by a rapid growth of these amorphous zones.