Comparative study of drain and gate low-frequency noise in nMOSFETs with hafnium-based gate dielectrics

In this paper, complementary measurements of the drain and the gate low-frequency noise are used as a powerful probe for sensing the hafnium-related defects in nMOSFETs with high-k gate stacks and polysilicon gate electrode. Drain noise measurements indicate that for low hafnium content (23%) and thin high-k thickness (2 nm), the defect density at the substrate/dielectrics interface is similar to the case of conventional SiO2. Gate-noise measurements suggest that the defect density in the bulk of the high-k gate stacks and at the gate/dielectrics interface is strongly degraded by the hafnium content.