Observation of deep levels and their hole capture behavior in p-type 4H-SiC epilayers with and without electron irradiation

Abstract

This paper reports deep levels in p-type 4H-SiC epilayers with and without electron irradiation by the current deep level transient spectroscopy. We also estimated time constants of hole capture by deep levels and discussed possibility that the deep levels behave as recombination centers.

Depth Distribution of Defects in SiC PiN Diodes Formed Using Ion Implantation or Epitaxial Growth

“…Considering the peak temperature and E A , PI1 and PI2 appear to be similar to those observed in electron-irradiated Al-doped p-type 4H-SiC. [19] PI3 corresponds to the Z 1/2 center, whereas PI4 and PI5 correspond to the RD 1/2 and EH 6/7 centers, respectively. [20,[29][30][31][32] The parameters for the deep levels and the speculated corresponding centers are summarized in Table 2.…”

“…In addition, it has been reported that the negative peak signals in the n‐type semiconductor, such as PI1 and PI2, originate from the hole‐like traps, [ 33,34 ] and E A of PI1 and PI2 are similar to the deep levels observed by DLTS for p‐type SiC. [ 19 ] Therefore, we consider that these peaks originate from the hole traps in the n‐type layer, and minority carriers might be injected to the hole traps by reverse currents during the filling pulse with ≈10 −9 A cm −2 . In addition, considering the correspondence with the reported 17A‐1 and e17‐1 centers, [ 18 ] PI1 and PI2 will originate from intrinsic or complex Al‐related defects.…”

“…e17A-1 [19] PI2 0.21 1.6 Â 10 À17 3.3 Â 10 12 e17-1 [19] PI3 the pn junction. Considering the sample structure, concentrations of defects generated by ion implantation should be high at the surface and gradually decrease with depth.…”

“…To date, there have been several reports on the defects induced by Al‐ion implantation using deep‐level transient spectroscopy (DLTS) and cathodoluminescence (CL). [ 19–25 ] The Al‐induced defects observed by DLTS were on the order of 10 13 cm −3 within a depth of ≈2 μm from the implanted regions. [ 19–22 ] CL studies have observed a distribution to ≈10 μm from the implanted region.…”

“…[ 19–25 ] The Al‐induced defects observed by DLTS were on the order of 10 13 cm −3 within a depth of ≈2 μm from the implanted regions. [ 19–22 ] CL studies have observed a distribution to ≈10 μm from the implanted region. [ 23,24 ] However, even defects with concentrations of 10 12 cm −3 reduce the carrier lifetimes, [ 4 ] and the presence of defects in the drift layer is critical for a conductivity modulation.…”