Trap Centers in Germanium-Implanted and in As-Grown 6H-SiC

Abstract

We have investigated the trap centers in germanium (Ge)-ion-implanted SiC(6H-SiC:Ge) and in as-grown SiC(AG:6H-SiC) samples using photoluminescence (PL) and deep-level transient spectroscopy (DLTS). Three carbon-vacancy related luminescence peaks were observed in 6H-SiC:Ge in PL measurements. Six electron trap centers were observed both in 6H-SiC:Ge and in AG:6H-SiC by DLTS. These trap-center-related peaks disappeared from both 6H-SiC:Ge and AG:6H-SiC after surface oxidation and subsequent removal of the oxide layers. Germanium atoms related to donor-type deep level at 1.2 eV below the conduction band edge is observed in 6H-SiC:Ge by DLTS. The six common trap centers are related to native defects. The deep-level activation energy, concentration and capture cross section are estimated.