Raman Investigation of the Effect of Metal Impurities at Gettering Sites on Phonon and Electron Related Properties of 4H-SiC n-n⁺ Junctions

We report on the application of introducing gettering sites as an approach to control some phonons and charge carrier related properties in 4H-SiC epilayer. Helium implantation (at room temperature or 750 degrees C) was first carried out, followed by a proper annealing and gold diffusion, in order to check the gettering efficiency. Raman measurements showed the presence of the desired defect, introduced by ion implantation at RT. The shift of the Fano interference allowed us to calculate the free carriers' density in each sample. The lowest value was found for the sample implanted at RT. The gettering sites can act as majority carrier traps and reducers of recombination processes, which can be interesting for devices designed for the detection of radiations.