| dc.description.abstract | In this dissertation, the basic mechanisms of total-ionizing-dose (TID) responses of Gate-All-Around (GAA) FETs and Charge-Trap Transistors (CTT) with FinFET architecture are studied. First, we investigate the TID response of highly-scaled bulk GAA Si nanowire CMOS transistors. nFETs and pFETs show comparable TID sensitivities. DC measurements demonstrate outstanding ionizing radiation tolerance due to enhanced electrostatic gate control and suppression of parasitic leakage current. Prominent traps located in both the SiO2 and HfO2 dielectrics are observed before and after irradiation; these are most likely due to oxygen vacancies and/or hydrogen complexes. Second, we evaluate the TID response of as-processed, irradiated, programmed, and erased 14-nm bulk Si CTTs. Significant random telegraph noise (RTN) is observed in as-processed 2-fin devices. TID increases the uniformity of effective border-trap energy distributions. Programming/erasing leads to activation/deactivation of prominent individual traps, but underlying, featureless 1/f noise magnitudes are not affected significantly. These results confirm the increasing importance of RTN in TID response for highly-scaled devices with advanced architectures. | |
