RF/Analog Performance Optimization and Assessing Linearity/Distortion FoMs of HDDP-DG-NCFET for Terahertz Applications

The burgeoning interest in non-classical MOSFET devices for low power applications and their latest incorporation in the newer technology node necessitate a study of Negative Capacitance Field Effect Transistors (NCFETs) in Radio Frequency applications. This work explores the comparative analysis of RF/analog performance of single gate NCFET (SG-NCFET) and highly doped double pocket double gate NCFET (HDDP-DG-NCFET) using performance parameters such as cut-off frequency (f_T), transconductance frequency product (TFP) and transconductance generation factor (TGF). The Metal Ferroelectric Insulator Semiconductor based HDDP-DG-NCFET excels SG-NCFET in terms of enhanced performance in TGF and TFP. In addition, several important distortion parameters, such as intermodulation distortion and linearity, are also investigated for these devices. The behavior of distortion and linearity indices such as g_m2, g_m3 (higher-order transconductance), IIP₃ (3rd order power-intercept point), higher order voltage intercept points (VIP₂ and VIP₃), 1 dB compression point, and total harmonic distortion is analyzed, which shows that HDDP-DG-NCFET exhibits distortion less performance. The influence of ferroelectric thicknesses and temperature on the RF/analog and linearity performance are also explored and described. The HDDP-DG-NCFET exhibits an ON current of 2.1 × 10⁻³ A/ \(\upmu\) $\mathrm{\mu }$ m, current switching ratio of 0.79 × 10¹⁰, g_m of 18.9 mS, f_T of 2.65 THz, TFP of 64 THz/V, which is 55.56%, 111.27 times, 134.79%, 55.88%, 255.56%, respectively higher than SG-NCFET device. In addition, the subthreshold swing and OFF current of HDDP-DG-NCFET are 25.5 mV/decade and 2.65 × 10⁻¹³ A/ \(\upmu\) $\mathrm{\mu }$ m, which is lesser than SG-NCFET. Moreover, it is witnessed that as the temperature rises from 250 to 400 K, RF/analog metrics are worsened while the linearity performance parameters are enhanced. Furthermore, it is observed that the proposed HDDP-DG-NCFET is linear compared to SG-NCFET with a lower magnitude of higher-order harmonics. Finally, these findings reveal that at lower voltages, HDDP-DG-NCFET outperforms SG-NCFET, evincing potential use of the same in RF applications.