We studied the epitaxial TiN(001)/Ge2Sb2Te5(001) (GST) interface of interest for applications in phase change nonvolatile 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 A 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 gamma= 50 meV/A^2. The surface energy of TiN(001) and GST(001) are gamma=81 and 10 meV/A^22 resulting in an adhesion energy of gamma=41 meV/A^2. 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.
Mandelli, D., Caravati, S., Bernasconi, M. (2012). Density functional study of the TiN/Ge2Sb2Te5 interface. PHYSICA STATUS SOLIDI B-BASIC RESEARCH, 249(11), 2140-2144 [10.1002/pssb.201248290].
Density functional study of the TiN/Ge2Sb2Te5 interface
BERNASCONI, MARCO
2012
Abstract
We studied the epitaxial TiN(001)/Ge2Sb2Te5(001) (GST) interface of interest for applications in phase change nonvolatile 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 A 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 gamma= 50 meV/A^2. The surface energy of TiN(001) and GST(001) are gamma=81 and 10 meV/A^22 resulting in an adhesion energy of gamma=41 meV/A^2. 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.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
