Impact of the starting interstitial oxygen concentration on the electrical characteristics of electron irradiated Si junction diodes

This paper studies the effect of the initial interstitial oxygen concentration on the electrical characteristics of high-energy electron irradiated Si n+p junction diodes. Emphasis is on the low frequency noise behaviour in forward operation, which is correlated with the static curren-voltage characteristics. It is shown that diodes processed in float-zone wafers give rise to a post-radiation reduction of the noise over a considerable forward bias range, while Cz devices tend to show an increase of the noise after electron irradiation. The observed noise behaviour, both before and after irradiation, cannot be explained by standard theories. Adequate modelling should take into account the generation-recombination centres in the substrate as a primary noise source.