Dose enhancement due to interconnects in deep-submicron MOSFETs exposed to X-rays

We present the first experimental report of dose-enhancement effects due to interconnects in deep-submicron CMOS, using ad-hoc designed MOSFETs with different metal layouts. We demonstrate that the presence of metal-1 tracks in the proximity of the device active areas may significantly modify the response to X-rays. The impact of the secondary electron emission from metal-1 layers is strongly dependent on the relative position to the transistor lateral isolation and LDD spacers.