High-performance AlN/β-Ga2O3 MOSHEMT biosensor: next-generation biomolecular sensing

Abstract

An AlN/β-Ga 2 O 3 MOSHEMT-based device with a cavity on the drain side beneath the gate to detect neutral and charged biomolecules is presented. The β-Ga 2 O 3 material is well suited for forming a heterostructure with AlN owing to its excellent lattice match, which leads to a lower interface trap density. Due to greater chemical stability and high density of surface hydroxyl groups, Al 2 O 3 is chosen as the sensing membrane. This enables silanization and chemical modification of the sensing membrane. Furthermore, to ensure strong biomolecule linkage, 3-aminopropyltriethoxysilane (APTES) is used for surface functionalization. This introduces terminal amine groups, which enable active binding sites for biomolecule adhesion. In this work, neutral and charged biomolecules are assessed using dielectric and interfacial charge modulation methodologies, respectively. The biomolecules interact with the sensing surface, modify the energy band and channel potential profiles, resulting in significant shifts in the device’s threshold voltage and drain current. The channel conductance, threshold voltage sensitivity, and drain current sensitivity are assessed across various biomolecules. The device achieves an average voltage sensitivity of 20.94% and 17.77% for neutral and charged biomolecules, respectively. The observed average current sensitivities are 12.35% and 13.51% for neutral and charged biomolecules, respectively. The results demonstrate that the device is a highly sensitive, label-free platform for biosensing applications.