Phosphorus-doped SiC as an excellent p-type Si surface passivation layer

Abstract

The passivation properties of phosphorus-doped amorphous silicon carbide (a-SixC1−x) layers on monocrystalline Si wafers (floating zone, 1Ωcm) have been investigated. The cleaning and the deposition process were performed in our two source (microwave, radio frequency) plasma-enhanced chemical vapor deposition reactor. In situ plasma etching and deposition at 350°C without any following annealing step led to extraordinary low surface recombination velocities of less than 5cm∕s for injection levels between 1×1014 and 1×1015cm−3. Characterization of the a-SixC1−x layer was done with quasi-steady-state photoconductance, microwave-detected photoconductance, and carrier density imaging techniques. For injection levels of more than 1×1015cm−3 the effective lifetime was limited only by intrinsic Auger recombination.