Properties of TaSiN thin films deposited by reactive radio frequency magnetron sputtering

TaSiN is a promising material for application as electrically conductive diffusion barrier for the integration of high permittivity perovskite materials in integrated circuits. TaSiN thin films were deposited by reactive radio frequency magnetron sputtering using TaSi and TaSi2.7 targets in an Ar/N2 atmosphere. The sputter power was varied in order to achieve different TaSiN compositions. The stoichiometry of as-deposited films was estimated using Rutherford backscattering spectroscopy. The as-deposited TaSiN thin films are amorphous. Their crystallization temperature is above 700 °C and increases with higher nitrogen content. They have metallic conduction and ohmic behavior. The resistivity of as deposited films is in the range from 10− 6 Ω m up to 10− 3 Ω m and increases with nitrogen content. It was found that p++-Si/Ta21Si57N21 develops unacceptable high contact resistance. Introducing an intermediate Pt layer the stack p++-Si/Pt/Ta21Si57N21 had a good conductive properties and good thermal stability at 700 °C.

► Stability of reactively sputtered TaSiN thin films as conductive diffusion barrier.
► Excellent properties after annealing at 700 °C in oxide atmosphere.
► Stable phase and amorphous with good conduction after annealing at 700 °C.
► Extension of ternary phase composition (lower N, higher Si) for barrier application.
► Ta21Si57N21 shows best properties as conductive barrier with perovskite dielectrics.