Thermal Deactivation of Boron-Oxygen Defects in Compensated n-Type Silicon

There are at least two distinct pathways for deactivating the defect complexes responsible for the detrimental light induced degradation in silicon wafers containing both boron and oxygen. One method widely used in the photovoltaic industry is regeneration of the fully formed recombination active defects through simultaneous carrier injection and annealing. This regeneration is a post-processing step that also mitigates light- and elevated temperatureinduced degradation often occurring in hydrogenated solar cells. A second approach capable of reducing the extent of the boron-oxygen related degradation involves thermal deactivation of the defect complexes in a pre-processing step. This work shows that thermal deactivation will reduce the scope of the boron-oxygen related degradation in compensated n-type silicon wafers, i.e. wafers containing a minority concentration of boron in addition to the phosphorus donors. Thermal deactivation is a pre-processing step that can be combined with the low temperature silicon heterojunction solar cell production process.