Fast Recombination of Excess Carrier in 6H-SiC

Fast carrier recombination phenomena in 6H-SiC has been investigated. Evaluation of carrier recombination in nitrogen doped n-type 6H-SiC grown by the Lely method have been carried out using picosecond photoconductivity, time-resolved photoluminescence and dynamic gratings (DG) techniques. From photoluminescence measurements the hole capture by neutral (nitrogen) donors is discussed. The hole capture times and capture cross sections 820 ps, 2.32 ns and 1.5-10-15cm2, 1.2-10-15cm2, respectively, by each of the inequivalent donor were evaluated. From the photoconductivity measurements the electron lifetimes ~ 1.5 μs at 300 K and (3.5a6.5)μs at 125 K were obtained. The ambipolar diffusion coefficient 1.4 cm2.s-1 obtained from dynamic gratings measurements is in good coincidence with the calculated values.