NBTI-channel hot carrier effects in PMOSFETs in advanced CMOS technologies

In this work the reliability of a 0.35 μm p+ poly-gate pMOSFET CMOS technology under conductive channel hot carrier conditions is investigated. It is found that at any bias and temperature condition applied, the degradation of sufficiently short channel length (Leff≃0.14 um) devices results in a reduction in drive current due to the impact of donor type interface trap generation and positive charge formation during the stress. At these dimensions the degradation is controlled by a contribution of both Negative Bias Temperature Instability (NBTI) and Channel Hot Carrier (CHC) mechanism. We will show the role that each of these two mechanisms play in determining the shift of typical device parameters. A methodology to decouple the two effects is also provided allowing to quantify each contribution separately at any bias and temperature condition. A conductive CHC model that takes into account the impact of both mechanisms to the device lifetime at the worst observed degradation condition (Vg=Vd) is also discussed