# Comparison of Various Factors Affected TID Tolerance in FinFET and Nanowire FET
## 3 Results and Discussion
(**a**) The \(\mathrm{V_{G}}\)-transient time; (**b**) the \(\mathrm{V_{T}}\) shift due to the interface trap. The 5 ch-NW had a larger oxide area than the FinFET. Therefore, it was reflected to have a greater TID effect and a larger V\({}_{\rm T}\) shift. However, these were less in the case of the 5 ch-NW because of superior gate controllability. The GAA structure improved the gate controllability because all the sides are covered with the gate. This does not only address SCE, but also improves tolerance to the TID effect [28]. Structurally, the oxide area of 5 ch-NW was approximately 96.1 nm\({}^{2}\), which is larger than that in FinFET. However, the TID effect in 5 ch-NW was less than that in FinFET in the above-mentioned experiment. Therefore, it shows that the gate controllability factor is more crucial than the oxide area in TID effect suppression. Figure 5: I\({}_{\rm D}\)-V\({}_{\rm G}\) curve shifts with an increasing radiation dose up to 100 Mrad for (**a**) FinFET, and (**b**) 5 ch-NW. The I\({}_{\rm D}\)-V\({}_{\rm G}\) curves were extracted at 100 krad, 1 Mrad, 10 Mrad, and 100 Mrad. These graphs were obtained by sweeping V\({}_{\rm DD}\) = 0.65 V and V\({}_{\rm G}\) from 0 V to 0.7 V when the total dose was reached. (**c,d**) are the I\({}_{\rm D}\)-V\({}_{\rm G}\) curve graph of the log scale of each device according to the TID effect. (**c**) is the FinFET’s log scale curve, (**d**) is the 5 ch-NW’s log scale curve, (**e**) is the FinFET’s transconductance graph, and (**f**) is the 5 ch-NW’s transconductance graph. Figure 7 depicts a graph of the TID simulation result with VDD set at 0.1 V and 0.65 V. In Figure 7c, at higher radiation, the VT shifts significantly than in the case of lower radiation because of the hole traps in the FinFET and 5 ch-NW. Additionally, because of the strong TID effect, the FinFET and 5 ch-NW are less affected by VDD at the higher radiation. However, the FinFET is affected by VDD when low radiation is applied, because the gate controllability of the FinFET is weaker than that of the 5 ch-NW. Therefore, the 5 ch-NW is not significantly affected by VDD. Table 3 lists the VT shift according to the variation of VDD. In the case of 5 ch-NW, there was almost no change owing to its better gate controllability, which reduced the VDD influence. Figure 6: FinFET and 5 ch-NW extracted the VT shift amount according to the increasing TID. Figure 7: Simulation results according to VDD variation (**a**) FinFET curves, (**b**) 5 ch-NW curves. (**c**) Comparison of the VT shifts of FinFET and 5 ch-NW. Figure 8 shows that the \(\mathrm{I_{D}}\)-\(\mathrm{V_{G}}\) changed due to the TID effect. Figure 8a shows the \(\mathrm{I_{D}}\)-\(\mathrm{V_{G}}\) of the FinFET, and Figure 8b shows the \(\mathrm{I_{D}}\)-\(\mathrm{V_{G}}\) of the 5 ch-NW. We can see that the \(\mathrm{V_{T}}\) changed and how it was different if the channel doping was changed. First, the \(\mathrm{V_{T}}\) decreased due to the TID effect, and the \(\mathrm{V_{T}}\) decreased on the same way when the channel doping was changed. In the case of channel doping at \(1\times 10^{16}\) cm\({}^{-3}\), it was confirmed that the \(\mathrm{V_{T}}\) variation due to the TID effect was similar to the \(\mathrm{V_{T}}\) variation at \(1\times 10^{18}\) cm\({}^{-3}\). Therefore, the \(\mathrm{V_{T}}\) increased when the channel doping increased in both the FinFET and 5 ch-NW, and the \(\mathrm{V_{T}}\) decreased due to the TID effect at both \(1\times 10^{16}\) cm\({}^{-3}\) and \(1\times 10^{18}\) cm\({}^{-3}\). Table 4 lists the \(\mathrm{V_{T}}\) variation based on channel doping. The doping of the FinFET changed from \(1\times 10^{16}\) cm\({}^{-3}\) to \(1\times 10^{18}\) cm\({}^{-3}\), and that of the 5 ch-NW was also changed in a similar way. Increasing channel doping in FinFET and 5 ch-NW caused an increase in the initial \(\mathrm{V_{T}}\). In addition, when radiation was applied, the \(\mathrm{V_{T}}\) and the TID effect decreased for all cases, regardless of doping.