In this work, the evolution of the excess conductivity of the YВа₂Сu₃О_7−δ single crystals under electron irradiation is studied. It is shown that irradiation with electrons leads to a significant expansion of the temperature interval that excess conductivity exists. Therefore, the value of the transverse coherence length ξ_с(0) increases by a factor of 1.4 and the point of the 2D–3D crossover shifts with respect to the temperature.