Chemical and physical limits on the performance of metal silicate high-k gate dielectrics

This research identifies four significant limitations on the performance of high-k alternative gate dielectrics that derive from inherent relationship s between (i) chemical bonding and physical properties, and (ii) device ope ration. These include interfacial band offset energies, thermal stability a gainst chemical phase separation, coordination dependent dielectric constan ts, and interfacial fixed charge. Then these are applied to transition meta l silicate alloys, e.g., (ZrO2)(x)(SiO2)(1-x). The paper also includes resu lts for other high-k oxides, Al2O3 and Ta2O5, and their alloys that relate to the issues addressed in this paper, and in particular help to put the re sults on the silicate alloys into a better perspective. This portion of the paper provides additional perspective with regard to the differences in th e chemical and physical limitations of elemental oxides and binary oxide al loys. (C) 2001 Elsevier Science Ltd. All rights reserved.