The hole lifetime tau(p) in the n-base and isothermal (pulse) current-voltage characteristics have been measured in 4H-SiC diodes with a 10 kV blocking voltage (100 mu m base width). The tau(p) value found from open circuit voltage decay (OCVD) measurements is 3.7 mu s at room temperature. To the best of the authors' knowledge, the above value of tau(p) is the highest reported for 4H-SiC. The forward voltage drops V-F are 3.44 V at current density j = 100 A/cm(2) and 5.45 V at j = 1000 A/cm(2). A very deep modulation of the blocking base by injected non-equilibrium carriers has been demonstrated. Calculations in term of a simple semi-analytical model describe well the experimental results obtained. (c) 2006 Elsevier Ltd. All rights reserved.