The behaviour of deuterium incorporated into the buried oxide of SIMOX

The buried oxide (BOX) layer of SIMOX samples was implanted with 20-30 keV D+ ion implantation at doses from 10(14) to 10(16) cm(-2). Other samples we re exposed to pure deuterium gas (0-1 MPa) at temperatures in the range 800 -1100 K. Thermal desorption spectrometry (TDS) revealed two main trapping s ites for deuterium in the buried oxide, The first releases deuterium at sim ilar to 900 K (activation energy similar to2.5 eV) and the second at simila r to 1250 K (activation energy similar to3.4 eV), They are attributed to di ssociation of Si-D and Si-OD groups, respectively. The first peak is domina nt in the implanted samples while the second is the dominant one for sample s exposed to deuterium gas. The formation of the Si-OD groups is a temperat ure-activated process. The trapping of deuterium in the implanted samples i s related to implantation-induced vacancy-like defects that are detected by means of positron beam analysis (PBA). Annealing at 900 K leads to a compl ete defect recovery. Deuterium profiling by SIMS confirms the trapping in t he defects. (C) 2001 Elsevier Science B.V, All rights reserved.