Ab initio Study of Tantalum Nitride and Silver Adatoms

• Other Authors: Grumski, Michael (Author)
• Format: Doctoral Thesis
• Language: English
• Published: 2012
• Subjects: Materials Science; Physics; Quantum physics; Density Functional Theory; Interconnect; Silver Adatom; Silver Interface; Tantalum Nitride
• Online Access: http://hdl.handle.net/2286/R.I.14745

abstract: In 2022, integrated circuit interconnects will approach 10 nm and the diffusion barrier layers needed to ensure long lasting devices will be at 1 nm. This dimension means the interconnect will be dominated by the interface and it has been shown the interface is currently eroding device performance. The standard interconnect system has three layers - a Copper metal core, a Tantalum Adhesion layer and a Tantalum Nitride Diffusion Barrier Layer. An alternate interconnect schema is a Tantalum Nitride barrier layer and Silver as a metal. The adhesion layer is removed from the system along with changing to an alternate, low resistivity metal. First principles are used to assess the interface of the Silver and Tantalum Nitride. Several stoichiometric 1:1 Tantalum Nitride polymorphs are assessed and it is found that the Fe2P crystal structure is actually the most stable crystal structure which is at odds with the published phase diagram for ambient crystal structure. The surface stability of Fe2P-TaN is assessed and the absorption enthalpy of Silver adatoms is calculated. Finally, the thermodynamic stability of the TaN-Ag interconnect system is assessed. === Dissertation/Thesis === Ph.D. Materials Science and Engineering 2012