The beneficial impact of a p–p+ junction on DC and analog/radio frequency performance of a vertical super-thin body FET

This article investigates the impact of the p–p⁺ junction (at the body-substrate interface) on different direct current (DC) and analog/radio frequency (RF) performance parameters of a newly invented structure called vertical super-thin body field effect transistor (VSTB FET) through a well-calibrated TCAD tool. At a fixed body doping, the influence of p–p⁺ junction was inspected for different substrate doping (N_s); which reveals that N_s has a robust control on the device electrostatics. Interestingly, higher N_s is seen to significantly suppress different short channel effects (SCEs), which in turn helps to improve various DC parameters excellently. An increase in N_s from 10¹⁵ to 10¹⁸ cm^?3 improves off-state leakage current and on-to-off current ratio by three orders of magnitude. Also, such a change in N_s decreases subthreshold swing and drain-induced-barrier-lowering by 8.78 mV/dec and 11.15 mV/V, respectively. The underlying physics behind such improvement at higher N_s is explored through the off-state channel electron density profiles corresponding to different N_s values. Further, different analog/RF parameters such as transconductance, input capacitance, gate-drain capacitance, output conductance, gain-bandwidth-product, and transconductance frequency product (TFP) show slight improvement for increasing N_s. In contrast, TGF, GFP, and GTFP offer large enhancement at higher N_s. This study is expected to demonstrate the significance of N_s on device performance.