Interface composition and band alignment issues in high-K gate stacks

In this paper, we describe the band structure and phase alignment by first principle DFT calculations to study the properties of the different crystalline structures of HfO/sub 2/ and ZrO/sub 2/. It is found that the band gap, barrier height and dielectric response of these two materials are phase dependent. Finally, as charge within the dielectric and at the interface remains a critical issue in high-K integration, we briefly discuss correlations between electrical properties, composition and band alignment.