New Theory of Effective Workfunctions at Metal/High-k Dielectric Interfaces -Application to Metal/High-k HfO2 and La2O3 Dielectric Interfaces

Abstract

We have constructed a universal theory of the work functions at metal/high-k HfO 2 and La 2 O 3 dielectric interfaces by introducing a new concept of generalized charge neutrality levels. Our theory systematically reproduces the experimentally observed work functions of various gate metals on Hf-based high-k dielectrics, including the hitherto unpredictable behaviors of the work functions of p-metals. Our new concept provides effective guiding principles to achieving near-bandedge work functions of gate metals. Moreover, we discuss the potential of the new high-k dielectrics of La 2 O 3 based on this new concept.