SEARCH

SEARCH BY CITATION

Keywords:

  • density functional theory;
  • electronic structure calculations;
  • Ge2Sb2Te5;
  • metal–semiconductor interfaces;
  • phase change materials;
  • TiN

Abstract

We studied the epitaxial TiN(001)/Ge2Sb2Te5(001) (GST) interface of interest for applications in phase change non-volatile memories by means of density functional calculations. The cubic phase of GST of interest for the memory devices was considered. From geometry optimization we found an equilibrium distance of about 3.0 Å between Ti and Te, Ge and Sb atoms located directly above along the [001] direction. The interface formation energy of a large 1440-atom model is γint = 50 meV/Å2. The surface energy of TiN(001) and GST(001) are γS = 81 and 10 meV/Å2 resulting in an adhesion energy of γad = 41 meV/Å2. A good adhesion between the two materials can thus be achieved in the ideal epitaxial configuration. The presence of metal induced gap states (MIGS) is revealed by the analysis of Kohn–Sham (KS) orbitals.