Revealing the Reliability Performance of a Dielectric-Modulated Negative Capacitance Junctionless FinFET Biosensor

In this study, we proposed a dielectric-modulated (DM) junctionless negative capacitance FinFET (JLNC-FinFET) to achieve precise label-free electrical detection of biomolecules, including streptavidin (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}=2.1$ </tex-math></inline-formula>), biotin (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}=2.63$ </tex-math></inline-formula>), APTES (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}=3.57$ </tex-math></inline-formula>), and Keratin (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}=8$ </tex-math></inline-formula>), within the designated cavity region. The proposed approach employs variations in the threshold voltage for which the sensitivity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S} _{\text {VTH}}\text {)}$ </tex-math></inline-formula> has a maximum value of 15.2% for pyridine (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}=12$ </tex-math></inline-formula>), serving as discerning metrics for detecting different neutral and charged biomolecules. The baseline junctionless (JL) FinFET, which is fabricated and characterized, in our previous publication, is opted for this study. Realizing the ferroelectric (FE) layer over its baseline counterpart offers a notable <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{\text {ON}}$ </tex-math></inline-formula>/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{\text {OFF}}$ </tex-math></inline-formula> improvement (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 10^{{4}}\text {)}$ </tex-math></inline-formula> in JLNC-FinFET. The reliability concerns of metal gate granularities (MGGs) and line edge roughness (LER) have been considered to explore the impact on biomolecule detection, i.e., biosensor sensitivity. The results reveal that larger grain sizes (GSs) exacerbate work function (WF) variability, especially with biomolecules resembled by high-K cavities. Moreover, the LER significantly impacts device parameters, which worsens the detection of biomolecules with high-K and LER amplitudes. Thus, the proposed study is worth exploring to acquire the design guidelines for reliability-aware biosensors.