The switching characteristics of 4H-SiC p-i-n diodes with 6 μ m long i-region were investigated in the 20÷ 500° C temperature ranges. It is shown that the diode reverse current increases with temperature and does not exceed 10(-7) A at temperature of 500° C (U-R = 100 V). The diode resistance r(F) at forward current of 40 mA decreases as temperature increases from 20 up to 500° C. The effective minority charge carrier lifetime in the i-region (r) was determined from the diode switching (from forward current to reverse voltage) characteristics; it was about 5 ns. As temperature increases from 20 up to 500° C, τ(p) increases by a factor of 3. We discuss the possibility of application of such diodes (i) in microwave switching facilities and (ii) as temperature sensors. A comparison is made between the parameters of 4H-SiC p-i-n diodes and those of Si p-i-n diodes with comparable values of calculated blocking voltage.