Semiconductors continue to get smaller with a tremendous increase in the density of devices that necessarily conduct electrons. Because of this density of functions and devices engineers and scientists are searching for practical and effective new materials that are non-conductive (dielectric) in order to build much smaller and viable gates through which electrons move without effecting parallel and overlapping operations.
Chip density and performance improvements have been driven by aggressive scaling of semiconductor devices. In both logic and memory applications, SiO2 gate dielectrics have reached its minimum thickness due to direct tunneling current and reliability concerns. Therefore high-k dielectrics have attracted a great deal of attention from industries as the replacement of conventional SiO2 gate dielectrics. So far, many of the candidate materials have been evaluated and Hf-based high-k dielectrics appears to be one of the promising materials for gate dielectrics. Это и многое другое вы найдете в книге Hf-Based High-k Dielectrics: Process Development, Performance Characterization, and Reliability (Synthesis Lectures on Solid State Materials and Devices) (Kim Young-Hee and Jack C. Lee)