Journal article

Characterization of GigaRad Total Ionizing Dose and Annealing Effects on 28 nm Bulk MOSFETs

This paper investigates the radiation tolerance of 28nm bulk n- and pMOSFETs up to 1 Grad of total ionizing dose (TID). The radiation effects on this commercial 28nm bulk CMOS process demonstrate a strong geometry dependence as a result of the complex interplay of oxide and interface charge trapping relevant to the gate-related dielectrics and the shallow trench isolation. The narrowest/longest-channel devices have the most serious performance degradation. In addition, nMOSFETs present a limited on-current variation and a significant off-current increase, while pMOSFETs show a negligible off-current change and a substantial on-current degradation. The postirradiation annealing annihilates or neutralizes oxide trapped positive charges and tends to partly recover the degraded device performance. To quantify the effects of TID and post-irradiation annealing, parameters including the threshold voltage, the free carrier mobility, the subthreshold swing, and the drain-induced barrier lowering are extracted.


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