In this work, we have reported the simulation study and electrical properties of MOS-HEMT with a cavity on the source side for bio-sensing applica- tions. The effect of the neutral and charged biomolecules on the sensitivity and concentration of electrons is an- alyzed. The increase of dielectric observed drain cur- rent decreases and increases due to the rise of the pos- itive charge of the biomolecules. The different cavity lengths are taken into consideration to analyze the per- formance of the device. The maximum threshold volt- age sensitivity obtained for keratin is 26% and 51% for charged biomolecules at 500mm cavity length. The ef fect of the AlGaN barrier mole fraction on sensitivity was also studied and optimized. The maximum sen- sitivity obtained is 74.04% for charged biomolecules. The device shows high stability under high-temperature conditions. The MOS-HEMT structure is optimized and analyzed using the ATLAS Silvaco device simulation tool.