Annealing and radiation effects on electrical properties of ALD-grown Al2O3 MOSCAPs: insights from C–V and G–V measurements

The annealing process impacts the electrical properties of Al₂O₃ MOSCAPs by altering defect densities and interface trap states. Annealing at 500 °C enhances structural integrity and optimizes capacitance, while higher temperatures lead to crystallization, increased interface defects, and SiO₂ interlayer formation, reducing capacitance. C–V and G–V measurements analyze interface states, series resistance, and oxide quality. To eliminate series resistance effects and determine electrical properties accurately, the Nicollian and Goetzberger method should be used. As frequency increases, the rearrangement time of trapped charges decreases, shifting the diffusion potential to more negative values. At high frequencies, interface state influence weakens, enabling more accurate doping concentration (Nd) determination, while barrier potential (Φ_B) decreases and carrier mobility increases. Radiation exposure reduces capacitance due to defect formation, altered charge carrier dynamics, and dielectric degradation. Radiation-induced positive charge accumulation and increased interface state density (N_it) cause a negative C–V curve shift and lower threshold voltage (Vth). Al₂O₃’s radiation sensitivity varies, with reported values from 0.0020 mV/Gy to 1.0 mV/Gy. This study measured 0.0035 mV/Gy. Comparatively, SiO₂ and non-ALD SiO₂ showed higher sensitivity, while HfO₂ demonstrated lower sensitivity.