Corona charge is used in the photovoltaic industry to help distinguish surface and bulk recombination. In this study, the deposition of corona charge on Si-SiO₂ structures was investigated. The magnitude and polarity of the charge was measured with a Kelvin probe, and its effect on surface recombination was measured by transient photoconductance.

For 5 Ωcm n-type samples with an oxide thickness of ~20 nm, a surface voltage of ~12 V (equivalent to a breakdown field of ~6 MVcm^–1) is the highest surface voltage achieved by positive corona charging. A surface voltage of twice that magnitude can be achieved by negative charging. The maximum surface voltage of either polarity is roughly halved when the structures include a ~70 nm thick TiO₂ layer. Such a layer provides favourable anti-reflection properties. This decrease in achievable surface voltage for Si-SiO₂-TiO₂ structures is a somewhat counterintuitive result that remains to be studied.

Photoconductance measurements indicate that surface recombination is affected by corona charge in two ways: (i) recombination decreases due to the repulsion of like-polarity carriers from the Si–SiO₂ interface, and (ii) recombination increases due charge-induced interface damage. These two effects were demarcated by removing the surface charge with isopropanol, as confirmed by Kelvin probe measurements.

The results of this study are consistent with those presented by Jin et al., extending them to include a quantification of charge density. It is found that interface damage is greater for negative corona charge, and that damage is incurred both with and without a TiO₂ coating.