Minority carrier lifetime measurements on 4H-SiC epiwafers by timeresolved photoluminescence and microwave detected photoconductivity

Abstract

Temperature dependent microwave detected photoconductivity MDP and time-resolved photoluminescence TRPL were employed to investigate the carrier lifetime in CVD grown 4H-SiC epilayers of different thickness. The minority carrier lifetime may be found from both the MDP and defect PL decay at room temperature for all epilayers, whereas the near bandedge emission (NBE) decay is much faster for thin epilayers (<17 µm) due to the substrate proximity and only follows the minority carrier lifetime for thicker samples at lower excess carrier concentrations.