Enhancement of diffusion barrier properties of Ta by plasma immersion ion implantation

Abstract

Ta(N) film was synthesized by implanting the nitrogen ions in Ta films employing Plasma Immersion Ion implantation (PIII) technique. Silicon wafers coated with Ta were implanted with nitrogen at two different doses. Nitrogen ions implanted in the film render it to become Ta(N), which in effect hinders the grain boundary diffusion. The ion implantation was carried out for two doses 10¹⁵ions/cm² and 10¹⁷ions/cm² corresponding to low and high dose regime. Thereafter a copper layer was deposited on the samples to produce Cu/Ta(N)/Si structure. To evaluate the barrier properties of Ta(N) these samples were annealed up to 700°C for 30 minutes. Sheet resistance, X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) measurements were carried out to investigate the effect of annealing.