A Charge-Based Analytical Model for MgZnO/ZnO MOS-HEMT Biosensor

Abstract

In this work, we have developed a physics-based analytical framework for a dielectric-modulated MgZnO/ZnO MOS-HEMT biosensor that can detect the biomolecules. Biomolecule dielectric modulation is linked with effective gate capacitance, 2-DEG density, surface potential, and drain current. The analytical baseline MgZnO/ZnO HEMT model shows excellent agreement with the experimental data, with coefficients of determination (R 2 ) of 0.9961 and 0.9987 for the transfer and output characteristics, respectively. Beyond conventional current-based sensing, the framework evaluates higher-order transconductances, quantum capacitance, gate charge, intrinsic capacitances, cut-off frequency, and thermal noise. Thermal-noise-limited signal to noise ratio (SNR) is evaluated to connect electrical sensitivity with intrinsic detectability. The further extension is the analytical evaluation of Z parameters Z 11 , Z 12 , Z 21 , and Z 22 to analyse the small-signal electrical response of the biosensor. The drain-on sensitivity of 37.3% is obtained using the proposed model.