Abstract <p>Driven by the ever-growing demand for device reliability in high-frequency and high-speed communication systems, this study focuses on the impact of defects properties on the electrical performance of InAlAs/InGaAs Schottky barrier diodes (SBDs). By incorporating defect models in 2D-device simulation profile, the current-voltage characteristics, series resistance, ideality factor, barrier height, and capacitance-voltage characteristics under varying defect concentrations were systematically investigated. The results show that as the defect concentration increases, the device’s series resistance rises significantly, the reverse leakage current increases, the ideality factor gradually deviates from the ideal value, the barrier height decreases, and the carrier concentration declines. Moreover, the acceptor defect is primarily responsible for performance degradation. Current decreases monotonically as defect energy level moves away from the conduction band edge, with minimal variation beyond 0.4 eV due to incomplete ionization of deeper acceptor states. These changes reveal the underlying physical mechanisms by which defects degrade device performance through the introduction of trap centers, the increase of tunneling effects, and carrier scattering.</p>