DC AND LOW-FREQUENCY NOISE CHARACTERISTICS OF GAMMA-IRRADIATED GATE-ALL-AROUND SILICON-ON-INSULATOR MOS-TRANSISTORS

This paper discusses the impact of gamma-irradiation on the static cur rent-voltage and low-frequency noise parameters of so-called gate-all- around (GAA) Silicon-on-Insulator n-MOSFETs. The devices are irradiate d up to a total dose of 30 Mrad(Si). The threshold voltage of the devi ces under test shows a rebound behaviour as a function of dose, i.e. a fter an initial reduction of V-T, an increase sets in resulting in a f inal value which is higher than the initial threshold voltage. A simil ar tendency is found for the normalised noise spectral density, i.e. a turnaround is observed, indicating a close relationship between the a bove two parameters. The maximum transconductance on the other hand de creases monotonously with dose. Because of the specific nature of the GAA device, an alternative procedure is proposed to extract the contri bution of oxide-trapped charge and interface charge to the total thres hold voltage shift, which yields a qualitative agreement with the meas urements.