High-Performance CNT-Based FETs on 200 mm Si Wafers With Low Drift and aM-Level Biosensing Sensitivity

Carbon nanotube (CNT) based ion-sensitive FETs (ISFETs) and biosensor FETs (BioFETs) provide scalable solutions for liquid electrochemical sensing. We present fab-compatible CNT-ISFETs fabricated on 200 mm wafers and evaluated under electrolyte gating, showing consistent threshold voltage (V_th) (0.45 ± 0.06) V, low gate leakage (10^-9 A), <10% on-current drift over 7 h, and <20% variation in key electrical parameters such as on-current, transconductance, threshold voltage, and subthreshold swing, demonstrating good deposition uniformity. After 3-Aminopropyltriethoxysilane functionalization, BioFETs exhibit I_on/I_off > 10⁴, a narrow V_th (0.31 ± 0.02) V, and a subthreshold swing of (101 ± 4) mV/dec, meeting relevant performance criteria. Upon functionalization for DNA sensing, our BioFETs achieve responsivities of >300% for 100 aM target DNA and ΔV_th ∼ 80 mV, marking the first instance of such low detection in label-free, non-nanoparticle-assisted CNT-FET biosensors.