Review on high-k dielectrics reliability issues

High-k gate dielectrics, particularly Hf-based materials, are likely to be implemented in CMOS advanced technologies. One of the important challenges in integrating these materials is to achieve lifetimes equal or better than their SiO2 counterparts. In this paper we review the status of reliability studies of high-k gate dielectrics and try to illustrate it with experimental results. High-k materials show novel reliability phenomena related to the asymmetric gate band structure and the presence of fast and reversible charge. Reliability of high-k structures is influenced both by the interfacial layer as well as the high-k layer. One of the main issues is to understand these new mechanisms in order to asses the lifetime accurately and reduce them.