Issues associated with p-type band-edge effective work function metal electrodes: Fermi-level pinning and flatband roll-off

Abstract

RESULTS AND DISCUSSIONIssues associated with the integration of p-type band-edge Through accurate EWF extraction, a wide variety of metal (5.0-5.2eV) effective work function (EWF) electrodes are identified electrodes have been evaluated. Figure 2 compares EWF on high-K and discussed. The Fermi-level (Ef) pinning effect traditionally used and SiO2. We find a similar span of EWF on high-K and SiO2 for the to explain the lowering of p-MOS EWF is believed not to be an material systems evaluated (4.2-5.0eV), even after a 1000°C anneal, intrinsic limitation. However, a new described as the "flatband (Vf) suggesting no indications of Ef pinning. Detailed comparison and rolloff effect" is shown to be the dominant factor.calculation of the results with the MIGS intrinsic model also suggests that intrinsic Efpinning by MIGS is not the limiting factor for p-type INTRODUCTION metal gates [20]. Scaling challenges require using metal gate electrodes to replace

Enabling Effective Work Function Tuning by RF-PVD Metal Oxide on High-k Gate Dielectric

“…However, one of the major challenges with gate first flow is to achieve and maintain desired effective work function and EOT after high thermal budget, typically requiring over 1000 °C. One way to achieve the desired effective work function is to use the dipole effect by adding metal elements into the highk dielectric film [1,2]. Metal oxide capping is one of the proven methods for this purpose [3].…”