The switching of high-voltage (1.5 kV) 4H-SiC gate turn-off thyristors (GTOs) by the dV/dt effect has been studied in the temperature range from 300 to 504 K. At a 30 us rise time of the forward bias V(t), the characteristic bias at which the structure under investigation can be switched on by the dV/dt effect decreases steadily from 289 V at room temperature (dV/dt similar to 9.7 kV/mu s) to 137 V at T = 504 K. The characteristic critical charge per unit area, Q(cr), equal to 1.9 X 10(-7) C/cm(2) at room temperature, also decreases steadily as the temperature increases. The main physical mechanisms that contribute to Q(cr) formation and the temperature dependence of the critical charge are qualitatively analyzed. The influence exerted by two-dimensional processes on the dV/dt switching is examined by making analytical estimates and using a computer simulation. The results obtained agree well with experimental data. (C) 2005 Elsevier Ltd. All rights reserved.