With ion striking at the gate center of N0 or N2 (shown in Fig. 1) with ion LET of 20 MeV·cm2/mg, 1D electrostatic potential variation with time (a) in conventional layout, (b) in conventional stacking layout, (c) in in-line stacking layout. The cut-point is at the depth of 10 nm, and the gate center of N0 or (N1 and N2).