Phosphorus-doped SiC as an excellent p-type Si surface passivation layer
The passivation properties of phosphorus-doped amorphous silicon carbide (a-SixC1-x) layers on monocrystalline Si wafers (floating zone, 1 Omega cm) 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 degrees C without any following annealing step led to extraordinary low surface recombination velocities of less than 5 cm/s for injection levels between 1x10(14) and 1x10(15) cm(-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 1x10(15) cm(-3) the effective lifetime was limited only by intrinsic Auger recombination.