Reduced Gate-Leakage Current and Charge Trapping Characteristics of Dysprosium-Incorporated Gate-Oxide n-MOS Devices

The higher effective barrier height of Dy₂O₃ , which is around 2.32 eV calculated from the Fowler-Nordheim plot, accounts for the reduced leakage current in Dy-incorporated HfO₂ n-type metal-oxide-semiconductor devices. The lower barrier height of HfO₂ characterizes the increasing electron-tunneling currents enhanced by the buildup of hole charges trapped in oxide, which causes a severe increase in the stress-induced leakage current (SILC), leading to oxide breakdown. However, the increased barrier height in Dy-incorporated HfO₂ inhibits a further increase in the electron tunneling from the TaN gate, and trapped holes lessen the hole-tunneling currents, resulting in a negligible SILC. The lower trap generation rate by the reduced hole trap density and the reduced hole tunneling of the Dy-doped HfO₂ dielectric demonstrate the high dielectric-breakdown strength by weakening the charge trapping and the defect generation during the stress.