## Results and Discussion
### GIDL and I\({}_{\text{ON}}\)/I\({}_{\text{OFF}}\) Ratio
The peak value of the electrical field near the drain side can be expressed in the following relationship: W40/\(L_{EX}=0\)\(\mu\)m \(>\) W200/\(L_{EX}=0\)\(\mu\)m \(>\) W200/\(L_{EX}=0.6\)\(\mu\)m \(>\) W40/\(L_{EX}=0.6\)\(\mu\)m. The higher the electric field peaks, the higher is the GIDL current. To clarify the improvement in the dependence of GIDL on \(L_{EX}\), the band-to-band generation rate (BTBT-GR) of W40 and W200 with \(L_{EX}=0\) and 0.6\(\mu\)m at \(V_{GS}=-3\) V and \(V_{DS}=18\) V were analyzed to explain the correlation between GIDL and \(L_{EX}\), as shown in Figures 8 and 9. The highest BTBT-GR for both W40 and W200 are located at the intrinsic drift/\(N^{+}\) junction, and its peaks are close to the surface at the drift/FP overlap region. The devices with \(L_{EX}=0.6\)\(\mu\)m had a lower BTBT-GR compared with those with \(L_{EX}=0\)\(\mu\)m, for which the GIDL was improved. Figure 8c and d show the BTBT-GR of W40 along with electric field contours near the intrinsic drift/\(N^{+}\) junction. The red area under the FP is the dominant tunneling region of the FinTFT. Owing to the lower longitudinal electric field in the FinTFT with \(L_{EX}=0.6\)\(\mu\)m, devices with extended wide drain were observed to have a lower GIDL. The BTBT-GR and electric field near the corner of W200 were higher than those towards the center, as shown in Figure 9c,d. In addition, the BTBT-GR, as well as the electric field in the corner of W40, were higher than those in the corner of W200. Therefore, W40 had a higher GIDL current than W200 owing to a higher BTBT-GR and the electric field near the corner. Figure 10 shows the \(I_{ON}/I_{OFF}\) ratio and I\({}_{ON}\) of W40 with various \(L_{EX}\) values at \(V_{DS}=18\) V. The ON-state current (\(I_{ON}\)) is obtained at \(V_{GS}=3\) V, and the off-state current (\(I_{OFF}\)) is obtained at \(V_{GS}=0\) V. As the \(L_{EX}\) increases, so does the \(I_{ON}\) of W40 with GFP and the \(I_{ON}/I_{OFF}\) ratio (shown in Figure 10a). Extending the wide drain region length leads to a large cross section in the current path and increases the \(I_{ON}\). However, when the FP is applied to extra-high voltage (\(V_{FP}=30\) V) instead of the gate voltage, the \(I_{ON}\) slightly decreases as the \(L_{EX}\) increases, as shown in Figure 5b. According to a previous study [26], when \(V_{FP}=30\) V, FinTFTs with wide drift have a high electron density concentrated at the corner of the drift and a low electron density at the non-corner region. Nevertheless, as the drift region of FinTFTs changed to multiple nanowire and each wire width was downscaled to nanometers, the corner and non-corner regions exhibited high electron density. Lower electron density in the FinTFTs with a wide drift (\(L_{EX}=0.6\)\(\mu\)m) leads to a low \(I_{ON}\). Therefore, the I\({}_{ON}\) of FinTFTs with \(L_{EX}=0\)\(\mu\)m is higher than that of that with \(L_{EX}=0.6\)\(\mu\)m. The FinTFTs with GFP not only achieved a high \(I_{ON}\) and \(I_{ON}\)/\(I_{OFF}\) ratio but also required no external bias. Figure 7: (**a**) Variation in the GIDL current with a wide drain length for W40 and W200 at \(V_{GS}=-3\) V and \(V_{DS}=18\) V. (**b**) Electric field distribution of W40 and W200 with \(L_{EX}=0\) and 0.6\(\mu\)m at \(V_{GS}=-3\) V and \(V_{DS}=18\) V.  
Figure 8: BTBT-GR of W40 with (**a**) \(L_{EX}\) = 0 \(\upmu\)m and (**b**) \(L_{EX}\) = 0.6 \(\upmu\)m and 3-D profile with electric field contours for (**c**) \(L_{EX}\) = 0 \(\upmu\)m and (**d**) \(L_{EX}\) = 0.6 \(\upmu\)m.  
Figure 9: BTBT-GR of W200 with (**a**) \(L_{EX}\) = 0 \(\upmu\)m and (**b**) \(L_{EX}\) = 0.6 \(\upmu\)m and 3-D profile with electric field contours for (**c**) \(L_{EX}\) = 0 \(\upmu\)m and (**d**) \(L_{EX}\) = 0.6 \(\upmu\)m.