We have studied the trapping of negative and positive charge in Si-implanted SiO2 layers of Al/SiO2/Si-based devices during high-field electron injection from the Si substrate under conditions typically used for obtaining electroluminescence. The location, capture cross section, and concentration of negatively and positively charged traps are determined in dependence on the time of heat-treatment by rapid thermal annealing (RTA). A comparison between the results obtained from Si- and Ge-implanted oxide layers is made. It is shown that in the case of Si-rich oxides an increase in the RTA time leads to the formation of hole and electron traps of high concentration, both of which are located within the oxide. For Ge-rich oxide layers, however, the hole traps are found primarily in the vicinity of the SiO2/Si interface while the electron traps are present within the oxide. The nature of these traps is discussed. (C) 2004 The Electrochemical Society.