The influence of total ionizing dose on the hot carrier injection of 22 nm bulk nFinFET

We investigate the hot carrier injection effect (HCI) and how X-ray radiation impacts the HCI of 22-nm nFinFETs as a function of device geometry and irradiation bias conditions in this paper. In the HCI test, the degradation of threshold voltage and saturation current decreases with the increase of fin number, which means that HCI weakens when the fin number increases. The reason is attributed to the coupling effect between fins. Moreover, irradiation is shown to weaken the degradation during the subsequent hot carrier test. The influence of irradiation on HCI is more obvious with ON bias than that of OFF bias and transmission gate bias. It is supposed that the Si–H bonds can be broken by irradiation before the HCI test, which is one reason for the irradiation influence on HCI. Besides, trapped charges are generated in the shallow trench isolation by the radiation, which could reduce the channel electric field, and then weaken the HCI. (paper)