I. Introduction
Multiple-Gate fin field-effect transistors (FinFETs) have received great attention in recent years owing to their inherent short-channel effect (SCE) immunity, near-ideal subthreshold slope, low leakage current, and process compatibility with conventional complementary metal oxide semiconductor (CMOS) technology [1]–[6]. Triple-gate MOSFETs provide enhanced electrostatic control of the silicon fin, which replaces the more usual planar silicon film of traditional silicon-on-insulator (SOI) MOSFETs. Omega-shaped MOSFETs are advanced triple-gate MOSFETs, where the omega-shaped gate wraps around most of the silicon fin. This particular device structure provides enhanced electrostatic control of the fin and of the buried oxide (BOX), owing to the additional lateral gates. The electrostatic control is sufficient to screen the radiation-induced charges in the BOX that usually degrade the electrical characteristics of transistors [7], [8]. The total dose response of fully depleted (FD) SOI devices in single-gate, double-gate, or triple-gate mode has been investigated previously [7]–[17]. The lateral coupling is dominant, leading to complex three-dimensional effects. These effects are geometry dependent, varying with the fin width. Experiments carried out on triple-gate MOSFETs for devices irradiated in the OFF bias configuration (seeTable I) show that the threshold-voltage shift induced by the positive charges in the BOX increases with the fin width [7], [8]. Bias Conditions for Irradiation of Triple-Gate MOSFETs
Gate Source Drain | |||
---|---|---|---|
ON | 1V | 0 V | 0 V |
OFF | 0 V | 0 V | 1 V |
TG 0 V-All | 0 V 0 V | 1 V 0 V | 1V 0 V |
1V-A11 | 1 V | 1V | 1 V |
−1 V-A11 | −1 V | −1V | −1 V |