Reduced gate-leakage current and charge trapping characteristics of dysprosium-incorporated HfO₂ gate-oxide n-MOS devices

Abstract

The higher effective barrier height of Dy2O3, which is around 2.32 eV calculated from the FowlerNordheim plot, accounts for the reduced leakage current in Dy-incorporated HfO2n-type metaloxidesemiconductor 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. © 2006 IEEE.