We have studied Si(111) substrates co-implanted with Ne and He, and also separately implanted with these ions, as a function of the annealing temperature. Ne implantations were performed up to fluences of 1 x 10(15) and 5 x 10(15) cm(-2) while keeping the substrate at 350 degrees C temperature. He implantations were performed at room temperature up to fluences of 5 x 10(15) and 1 x 10(16) cm(-2). The co-implanted samples were first implanted by Ne and then by He ions. These samples were submitted to rapid thermal annealing with temperatures ranging from 350 to 1000 degrees C. Rutherford backscattering spectrometry/channeling measurements have demonstrated temperature dependent beam dechanneling starting at the implanted ion region. The co-implanted system with 1 x 10(15) Ne/cm(2) and 1 x 10(16) He/cm(2) shows an improved dechanneling stability in the range of 400-800 degrees C. Transmission electron microscopy has demonstrated a bubble morphology of Ne-He similar to the sample implanted only with Ne, even for a Ne: He co-implantation ratio of 1:10. We have concluded that the observed dechanneling is mainly due to Ne residual implantation damage and that the annealing behavior of such systems is very different from the He implanted samples. (C) 2013 Elsevier B. V. All rights reserved.