Minority Carrier Lifetime Measurements on 4H-SiC Epiwafers by Time-Resolved 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 theMDP 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.

Defects in epitaxial 4H-SiC revealed by exciton recombination

“…In figure 4(b), the normalized photoluminescence decay of the excitonic band for SY EPI (F), SY EPI, SK EPI (F) and SK EPI is reported. The decay time values are in the range of 10-40 ns and are compatible with those reported in literature for analogous epilayer thickness [29]. The lifetime value of the excitonic band as a function of the sample position of the SY EPI wafer is reported in figure 2(d).…”