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

Abstract

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 (Ns); which reveals that Ns has a robust control on the device electrostatics. Interestingly, higher Ns is seen to significantly suppress different short channel effects (SCEs), which in turn helps to improve various DC parameters excellently. An increase in Ns 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 Ns 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 Ns is explored through the off-state channel electron density profiles corresponding to different Ns 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 Ns. In contrast, TGF, GFP, and GTFP offer large enhancement at higher Ns. This study is expected to demonstrate the significance of Ns on device performance.