Thermal stability of nanocrystalline W-Ti diffusion barrier thin films

Abstract

Nanocrystalline W-Ti diffusion barrier thin films with different phase structures and Cu/barrier/Si multilayer structures were deposited on p-type Si (100) substrates by DC magnetron sputtering. These films were annealed at different temperatures for 1 h. The diffusion barrier properties and thermal stability were studied using four-probe tester (FPP), XRD, AFM, XPS, FESEM, and HRTEM. The experimental results showed that the films were stable up to 700°C. When the annealing temperature was increased, the Cu and Ti atoms began to react and CuTi3 was formed. In addition, the high resistance Cu3Si was formed due to inter-diffusion between the Si and Cu atoms which made the surface rougher and caused the sheet resistance to increase abruptly. At the same time, failure mechanism of the nanocrystalline W-Ti diffusion barrier thin films during annealing process was also discussed. nanocrystalline W-Ti thin films, diffusion barrier, anneal, sheet resistance Citation:Wang Q X, Fan Z K, Liang S H. Thermal stability of nanocrystalline W-Ti diffusion barrier thin films.