Quantitative x-ray diffraction analysis of bimodal damage distributions in Tm implanted Al0.15Ga0.85N. (1st March 2016)

• Record Type: Journal Article
• Authors: Magalhães, S; Fialho, M; Peres, M; Lorenz, K; Alves, E
• Is Part Of: Journal of physics. Volume 49:Number 13(2016)
• Publication Date: 2016-03-01
• Subjects: AlGaN -- defects -- implantation -- x-ray diffraction -- strain -- ion channelling; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/49/13/135308
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: In this work radial symmetric x-ray diffraction scans of Al0.15 Ga0.85 N thin films implanted with Tm ions were measured to determine the lattice deformation and crystal quality as functions of depth. The alloys were implanted with 300 keV Tm with 10° off-set to the sample normal to avoid channelling, with fluences varying between 10 13 Tm cm −2 and 5 × 10 15 Tm cm −2 . Simulations of the radial 2 θ – ω scans were performed under the frame of the dynamical theory of x-ray diffraction assuming Gaussian distributions of the lattice strain induced by implantation defects. The structure factor of the individual layers is multiplied by a static Debye–Waller factor in order to take into account the effect of lattice disorder due to implantation. For higher fluences two asymmetric Gaussians are required to describe well the experimental diffractograms, although a single asymmetric Gaussian profile for the deformation is found in the sample implanted with 10 13 Tm cm −2 . After thermal treatment at 1200 °C, the crystal quality partially recovers as seen in a reduction of the amplitude of the deformation maximum as well as the total thickness of the deformed layer. Furthermore, no evidence of changes with respect to the virgin crystal mosaicity is found after implantation and annealing.