Electron mobility dependence of W/HFO ₂ gate stacks on interfacial layer preparation

Abstract

A spike anneal of the interfacial layer of a W/HfO 2 gate stack gave lower electron mobilities when compared with a stack which did not receive such spike anneal. These different values in mobility appear to be consistent with interfacial reaction suggesting silicate formation at the Si interface rather than due to interfacial layer re-growth. Densification of the interfacial layer after spike anneal may inhibit this reaction (silicate formation) at the interface producing lower electron mobilities.