Investigation of the Invariant Drain Current Point in Dielectric Modulated BESOI MOSFET Biosensor

The study of a dielectric-modulated biosensor built on the
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SOI MOSFET structure showed a crossing point of the transfer characteristics curves for target biomaterials with different dielectric constants (CID – Current Invariant Dielectric). The CID corresponds to an insensitive region for biosensing application, although it can be interesting as a reference signal measurement. It was evaluated that this behavior arises from the threshold shift and the transconductance increase as a function of the biomaterial dielectric constant. The gate voltage at the crossing point presented higher variation as a function of the metal gate-semiconductor workfunction difference, when compared to the influence of the programming gate voltage and the gate oxide charge concentration.