Figure 4.

(a) Doping gradient achieved by electron holography varying from 6 × 10¹⁸ down to 6 × 10¹⁷ cm^–3 with an exponential decay of 44 nm/decade. (b) Measured threshold voltage V_T dependence of gate position L_HSQ and a theoretical model considering the calculated doping gradient from electron holography. V_T is extracted at the linear mode of operation (V_DS = 50 mV) to suppress short channel effects. Five devices are measured for each gate position at L_HSQ < 90 nm and two devices for L_HSQ = 100 nm. The theoretical simulation considers fully doped cylindrical junctionless transistors.³⁶ (c) Frequency behavior of maximum transconductance g_m,max and oxide trap density derived from g_m,max vs frequency dispersion for varying gate position. N_bt is estimated by considering boarder traps responding within a region of 10⁸–10⁹ Hz corresponding to an oxide depth of about 0.1–0.3 nm when assuming elastic tunneling.³⁸