A molecular orbital model for the electronic structure of transition metal atoms in silicate and aluminate alloys

A classification scheme that separates non-crystalline dielectrics into three groups with different amorphous morphologies reveals an approximately linear relationship between oxygen atom coordination and average bond ionicity. When applied to transition metal (TM) and rare earth (RE) lanthanide oxides, and their silicate and aluminate alloys, this approach demonstrates a correlation between stability against crystallization and oxygen atom coordination. It also provides a local bonding model for local molecular orbital calculations that are based on the coordination and symmetry of TM and RE atoms and the orbital energies of their oxygen neighbors. These calculations provide important insights into the electronic structure of TM and RE dielectrics, and in particular the role of atomic d-state energies in providing a scaling parameter for conduction band offset energies between gate dielectrics and the Si substrate. (C) 2002 Elsevier Science Ltd. All rights reserved.