Design and Simulation of advanced boron-doped GaN cap layer on AlGaN/GaN MOSHEMTs for enhanced label-free biosensing applications

This study focuses on the design and simulation of a biosensor based on HEMT technology, with a focus on a GaN/AlGaN MOSHEMT architecture with a cavity and a boron-doped GaN cap layer, for identifying label-free biological molecules. The inclusion of a boron-doped GaN cap layer in the AlGaN/GaN heterostructure facilitates E-mode operation. We examined the influence of neutral or label-free biomolecules on the electron concentration and device sensitivity. The Sentaurus TCAD device simulation tool was used to analyze the MOSHEMT structure. Our findings suggest that low dielectric biomolecules increase the drain current, whereas higher dielectric values decrease the drain current. We also evaluated the device performance across various cavity lengths (100 nm, 200 nm, 300 nm, and 400 nm). The AlGaN/GaN MOSHEMT provides excellent sensitivity and precision in biological detection. The proposed GaN cap layer MOSHEMT biosensor is designed to detect biomolecules such as Keratin, Zein, ChOx, Biotin, Streptavidin, and Urease. The addition of these biomolecules to the nanocavity significantly enhances the drain current, transconductance (g_m), output conductance (g_d), and sensitivity. The device demonstrates high sensitivity (~ 73%) under optimized parameters, making it suitable for precise label-free biosensing applications.