Study of stress-induced leakage current (SILC) in HfO2/Dy2O3 high-κ gate stacks on germanium

In the present work we study reliability issues of Pt/HfO2/Dy2O3/n-Ge MOS structures under various stress conditions. The electrical characteristics of the micro-capacitors are very good probably due to the presence of a rare earth oxide as interfacial layer. It is shown that the injected charge (Qinj) at high constant voltage stress (CVS) conditions induces stress-induced leakage current (SILC) that obeys a power-law. We also observe a correlation between the trapped oxide charge and SILC, which is, at low stress field, charge build-up and no SILC, while at high stress field SILC but few trapped charges. Results show that the present bilayer oxides combination can lead to Ge based MOS devices that show acceptable degradation of electrical properties of MOS structures and improved reliability characteristics.