Characterization of the 2T1C unit cell. (A) Incremental step programming pulse (ISPP) waveform of V_w, varying from 0.5 to 2 V. Input pulse waveform of V_re. (B) Drain current I_d of T₂ with V_w varying from 0.5 to 2 V, where V_x = 0.1 V. (C) ISPP waveform applied to V_x, ranging from 0.1 to 0.4 V with 0.1 V increments. The pulse width was 0.1 s. (D) Corresponding I_d curves when V_w was fixed at a series of values.