Review on high-k dielectrics reliability issues

TLDR

High‑k gate dielectrics, especially Hf‑based materials, are poised for use in advanced CMOS technologies, yet achieving lifetimes equal to or better than SiO₂ is challenging because their asymmetric gate band structure and fast reversible charge create novel reliability phenomena that depend on both the interfacial and high‑k layers. The paper reviews the status of reliability studies of high‑k gate dielectrics, illustrates the findings with experimental results, and seeks to understand new mechanisms in order to accurately assess and reduce device lifetime. The authors review the status of reliability studies of high‑k gate dielectrics and illustrate the results with experimental data.

Abstract

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 SiO/sub 2/ 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.