Investigation of voltage processing window for point-contacting by localised dielectric breakdown

The robustness of the processing window for the Point-contacting by Localized Dielectric breakdown technique has been investigated. Previous results have shown that if the voltage is increased beyond the initial breakdown voltage then catastrophic breakdown will result leading to enhanced recombination. The difference between these breakdown events represents the safe voltage processing window of the technique. Results for amorphous silicon and silicon nitride as the passivating dielectric have been analyzed using the Weibull distribution and indicate that a large processing window without lifetime degradation is available. First breakdown for amorphous silicon is seen around 6V, with second breakdown for occurring at nearly ten times this value. For silicon nitride, the first breakdown is seen around 28V and second breakdown around 78V, a factor of three and a half. Results for both dielectrics show no overlap of the first and second breakdown distributions suggesting a robust process can be implemented using these commercially important passivating dielectrics.