Investigation of flicker noise in silicon diodes under reverse bias

This article analyses some connections between the reverse properties of silicon power diodes and their flicker noise under reverse bias conditions. It is shown that the presence of defects in the silicon surface near the pn-junction termination has a significant influence on both the reverse VA characteristics (RVAC) and the low-frequency power noise of diodes under reverse bias conditions. However, the inherent relationship between both effects becomes apparent only under special conditions and by the use of sophisticated measurements.The article presents a simple physical model, describing the behaviour and effect of surface structural defects on the silicon surfaces in connection with the reverse and noise properties of the tested diodes. The model identifies and consequently performs the mutual relationships with respect to the physical nature of the investigated defects.The most important practical contribution of this article is to identify a simple way to reveal latent defects of chip reverse properties undetected by the standard in-process inspection, and to rectify these defects by a simple operation process (e.g. chemical etching). This information has great importance for reasonable prognosis of devices’ reliability and lifetime, especially before encapsulation and introduction on the market.