Defect generation at charge-passivated Si-SiO₂ interfaces by ultraviolet light

The effect of surface charge on defect generation at the Si-SiO₂ interface by UV radiation is investigated. The surface charge is deposited by the corona method, and photoconductance and Kelvin probe measurements are used to characterize surface recombination and surface charge density. Both electron injection and defect generation are found to occur for significantly lower photon energies in the presence of a positive surface charge, with evidence that photons with an energy less than 3.66 eV are capable of generating interface defects. In contrast to previous studies on MOS structures, the majority of the defect generation is found to occur at oxide fields less than ∼1 MV/cm. A possible explanation is discussed in terms of the hydrogen-release model of the defect generation. These results have significant relevance to high-efficiency silicon solar cells.