In this work defects generated by argon implantation were studied both by Transmission Electron Microscopy (TEM) inspections and by measurements of the defect electrical activity at the oxide‐silicon interface and in the bulk. TEM analyses showed defects close to the surface for argon doses equal or larger than 1013cm‐2, and stacking faults in the sample implanted with 1015 cm‐2 dose. The maximum defect depth was about 50 nm. The generation lifetime was heavily degraded even with the lowest argon dose. Besides, positive charge and a relevant population of interface states were found to be related to argon implantation. In addition, DLTS revealed four deep levels starting with the samples implanted with 1013cm‐2 argon dose. These levels evolve with increasing the argon dose and are located much deeper than the defects revealed by TEM, i.e. down to a few micron depth. The dependence of the signal amplitude on the filling pulse width was analyzed, and showed that all the observed levels are related to extended defects. Kinetic Monte Carlo simulations of the implantation and annealing process indicate that argon atoms interact with implantation‐induced defects and enhance the formation of extended defects. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)