Slow photoconductivity decay in 3C-SiC on Si substrates

Abstract

N-type 3C-SiC layers grown on p-type (001) Si substrates were characterized by the conventional photoconductivity decay method. A N2 laser (337 nm wavelength) was used as the excitation source. A very slow component with a time constant larger than 1 ms was observed in the photoconductivity decay curves. A numerical simulation considering a trap with a very small capture cross section for electrons (<1×10−21 cm2) was able to reproduce main qualitative features of the experimental results. From comparison of the experimental decay curves with the theoretical ones, the following conclusions were drawn about the trap in 3C-SiC. (1) The trap level Et is close to the conduction band edge Ec(Ec−Et=0.1–0.15 eV). (2) The concentration is considered to decrease with increasing donor concentration.