Why and How Atom Intermixing Proceeds at Metal/Si Interfaces; Silicide Formation vs. Random Mixing

Abstract

Atom intermixing at metal/semiconductor interfaces is studied using the first-principles theoretical calculations. In this paper, by demonstrating atom-diffusion potentials and electronic structures of Au/Si, Al/Si, Au/GaN, Au/HfO2, Ni_xSi_y/Si and Au_xSi_y/Si systems, we answer various elementary questions concerning to the intermixing; what is the motive force of intermixing, how the intermixing proceeds, what are relevant factors to prevent the intermixing, what origins distinguish silicide formation from random alloying, why the silicide stoichiometry is limited on Si substrate, and how and why the Schottky barrier changes with varying the silicide stoichiometry.