Influence of the Source Composition on the Analog Performance Parameters of Vertical Nanowire-TFETs

The goal of this paper is to study the analog performance parameters of tunnel field-effect transistors (TFETs) with different source compositions and process conditions. The experimental matrix included devices with either a 100% silicon or Si
_1–x
Ge
_x
source, so that the germanium amount at the source/channel interface could be correlated with the prevailing transport mechanism and its impact on transconductance (gm), output conductance (
$g_{\mathrm {DS}}$
), and early voltage (
$V_{\mathrm {EA}}$
) could be analyzed. The used process conditions were highlighted by comparing a reference split with no Si passivation to the cases with 12 and 18 Si monolayers to determine their influence on the interface trap density and eventual reduction of the traps in the gate oxide. All these process parameters enable to make conclusions on the intrinsic voltage gain (
$A_{V}$
) and the low-frequency noise. Based on these results, the suitability of each type of TFET has been discussed, revealing that 100% Si may still be considered for analog applications depending on the bias conditions.