Defect formation and optical activation of Tb implanted AlxGa1-xN films using channeled implantation at different temperatures

[摘要] AlxGa1-xN (x = 0.20, 0.50, 0.63) films grown on (0001) sapphire substrates by metal organic chemical vapor phase deposition were implanted with Tb ions at 150 keV and a fluence of 7 x 10(14) Tb cm(-2). The implantation was carried out with the beam aligned with the c-axis and the implantation temperature was varied from room temperature (RT) to 550 degrees C. Additionally, post-implantation rapid thermal annealing was performed at 1200 degrees C during 120 s. The impact of implantation temperature on the damage accumulation is investigated. Rutherford backscattering spectrometry/channeling (RBS/C) measurements show that two damage regions are forming and the damage is not decreasing monotonically with the increase of implantation temperature. Bulk damage follows the same trend for all AlxGa1-xN compositions, increasing when the temperature is raised up to similar to 100 degrees C, and then decreasing for higher temperatures. A good agreement is observed between the damage accumulation obtained from RBS/C and the strain profile derived from symmetric (0002) 2 theta-omega. X-ray diffraction scans. Transmission electron microscopy results show the suppression of basal stacking faults after implantation at 550 degrees C. Tb lattice site location studies revealed two preferential sites: the substitutional cation site and a site displaced from that by 0.2 angstrom along the c-axis. A higher substitutional fraction of Tb ions is obtained for implantation temperature of 550 degrees C. The optical activity investigated by photoluminescence showed that after thermal annealing, the D-5(4) -> F-7(J) infra-4f(8) transition is detected in all the samples.

[发布日期] 2018-12-15

[效力级别]  Proceedings Paper

[关键词] Rutherford backscattering spectrometry/channeling;X-ray diffraction;Transmission electron microscopy;Photoluminescence;AlGaN