An insight to the performance of vertical super-thin body (VSTB) FET in presence of interface traps and corresponding noise and RF characteristics

摘要

We investigated vertical super-thin body (VSTB) FET performance in presence of different interface (HfO2/Si) trap distributions (uniform and Gaussian) and concentrations using TCAD tools. For trap concentration (TC) of 10(13) eV(-1) cm(-2), the percentage change in on-to-off current ratio (I-on/I-off) is 93.91% for uniform trap (UT) and 49.8% for Gaussian trap (GT) distribution. For the same TC, subthreshold swing (SS) shows percentage change of 5.1% for UT and 11.41% for GT distribution. Thus, the device performance shows good immunity for TC up to 10(13) eV(-1) cm(-2). However, for TC = 10(14) eV(-1) cm(-2) SS degrades significantly. The influence of traps on the cumulative effect of three noise sources (diffusion + generation-recombination/G-R + flicker) and on individual noise sources (G-R and diffusion) is explained qualitatively at low and high frequencies (f = 1 MHz and 10 GHz). The study shows that the overall noise cannot disturb the device performance at very high frequency. Various radio-frequency (RF) parameters like transconductance (g(m)), total input capacitance (C-gg), gate-drain capacitance (C-gd), unit-gain cutoff frequency (f(T)), and gain-bandwidth-product (GBP) are also studied for variation of trap types. For TC = 10(14) eV(-1) cm(-2), the percentage change in f(Tmax) (GBP(max)) is - 21.43% (- 8%) for UT and - 22.86% (- 9.6%) for GT distribution.