[en] Several models of charge losses at the entrance window of semiconductor detectors are described. Special attention was paid to losses of the charge carriers drifting to the entrance window for the model with a sink which is placed at a distance δ from the entrance surface of the detector. It was shown that the effective dead layer may be significantly thicker than dead layer δ especially in surface-barrier detectors when detecting charge partictes having the increasing specific ionization power at the end of their ranges