The Impact of High-k Dielectric Layers for SiNW-FET Biosensor Performance Improvement

This paper demonstrated the application of several dielectric materials with different dielectric constant (k) (i.e. silicon dioxide (SiO
2
), aluminium oxide (Al
2
O
3
), and hafnium oxide (Hf02) with
$k$
values of 3.9, 9.0, and 25.0, respectively) on the silicon nanowire (SiNW) surface in order to study their effect on the performance of SiNW field-effect transistor (SiNW-FET) biosensor through simulation tool. The biosensor structure was designed and simulated in Silvaco ATLAS. Different interface charge (Q
F
) values representing actual target biomolecules were applied onto different high-k dielectric materials surface covering the SiNW channel between drain and source as transducer for biomolecule interaction. With increase of
$k$
values exhibited by different high-k dielectric materials, the output drain currents (I
D
) of the biosensor were increased during detection of interface charges, which were applied on the surface of dielectric layers. Therefore, the biosensor's performance toward detection of interface charges was improved especially when Hf02 was used as dielectric layer for the biosensor with device sensitivity and limit of detection (LOD) of 17.32 µA/e·cm
²
and 1.82×10
¹⁰
electronic charge/cm
⁻²
, respectively.