Photoluminescence characteristics of rare earth ion-implanted SiO2/Si

The photoluminescence (PL) characteristics were studied for the ion-implanted Tb, Eu and Dy ions with the accelerated voltage 180kV into SiO2/Si, changing the annealing temperatures every 100 degrees C up to 1200 degrees C for an hour. Then, the thickness of thermally oxidized SiO2 film was determined as 400 nm from TRIM simulation and SMS atom analysis. At first from PL spectra, we found that the ion-implanted rare earth ions as mass-filtered monovalent states actually were both embedded as the trivalent states: Tb3+ and Eu3+, respectively. This suggested that accelerated RE ions had lost their own electrons generating lattice defects through colliding with SiO2 atoms. With increasing annealing temperatures, the intensities of PL lines at 544nm of Tb3+ ion increased more, reaching the maximum at 600 degrees C to disappear at 1000 degrees C. A peak at 280 nm observed commonly through all the specimens was identified as a hole-trapped O-vacancy defect or E' center created in SiO2 because the PL intensity decreased in response to the intensity of electron spin resonance (ESR) spectrum measured in parallel with the increasing annealing temperatures. (c) 2005 Elsevier B.V. All rights reserved.