Effects of Channel Implant Variation on Radiation-Induced Edge Leakage Currents in n-Channel MOSFETs

Bias Dependence of Total Ionizing Dose Effects on 28-nm Bulk MOSFETs

“…4a demonstrates a significant increase in the drain leakage current of nMOSFETs. This is closely related to the positive oxide-trapped charges in the thick STI oxides [11], [12], as seen in Fig. 4b.…”

Characterization and Modeling of Gigarad-TID-Induced Drain Leakage Current of 28-nm Bulk MOSFETs

“…We propose a semi-empirical physics-based approach with only three parameters to model the parallel parasitic and total drain leakage current as a function of TID. The lateral parasitic device has been investigated using TCAD device simulations [18]- [20], compact models [21], or a combination of these two approaches [15], [22]. However, these models involve complex device structures and intensive analytical computations.…”

“…Moreover, the complex channel doping engineering has been widely used in modern CMOS technologies, including the retrograde well for preventing the latch-up effect, the threshold voltage adjustment by ion implant at the surface, the lightly-doped drain (LDD) for suppressing the hot carrier degradation, and the halo implant for inhibiting the punchthrough effect [29]. This leads to a non-uniform doping profile [15], [18], as illustrated in Fig. 1.…”

“…The significant increase in the drain leakage current is mainly attributed to the radiation-induced charge trapping in relatively thick STI oxides. For an nMOSFET, trapped holes in STI oxides can invert the p-type substrate along the STI sidewalls and open two parallel parasitic leakage paths [12]- [15]. This allows two parallel leakage components to flow from drain to source, even when the main nMOSFET is switched off, as shown in Fig.…”

Influence of Halo Implantations on the Total Ionizing Dose Response of 28-nm pMOSFETs Irradiated to Ultrahigh Doses

“…When such devices are irradiated up to 1 Mrad(SiO2), they exhibit an increase in the off leakage, enhanced interface-trap buildup and greater 1/f noise [15] [16]. The influence of the halo on radiation-induced effects in Si- [18] were focused on the development of analytical models that describe the increase in the off-state leakage current in nMOSFETs, considering the charge buildup in the STI and the process variation of the doping profile along the sidewall regions of STI. It has been found that the high variability on the radiation-induced leakage current in nMOSFETs is caused by the statistical variation of the doping implantation process in the regions close to the STI [19].…”