An analytical approach to analysis of the switch-on process in silicon carbide (SiC) thyristors is taken. Expressions for the current rise time are obtained for both low, tau(rL), and high injection levels, tau(rH), in the blocking po-base of a thyristor, with account taken of the fact that the injection coefficient of the SiC p(+)n-junction is less than unity. It is shown that in 4H-SiC thyristors the tau(rL)/tau(rH) ratio may be as high as 25-30. The results obtained are in agreement with the available experimental data and computer simulations. (C) 2002 Elsevier Science Ltd. All rights reserved.