Low temperature deposition of tantalum diffusion barrier by filtered cathodic vacuum arc

摘要

Tantalum (Ta) diffusion barrier films were deposited on un-patterned and patterned silicon substrates at ambient temperature and without substrate bias by filtered cathodic vacuum arc (FCVA). The films were characterized by atomic force microscopy, scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, four-point resistivity probe and surface profilometer. It was found that the Ta film was 750 Angstrom thick and free of C and O except for surface contamination. The film morphology was smooth and uniform with root-mean-square roughness of similar to0.82 Angstrom. The Ta film was polycrystalline beta phase with a mean grain size of similar to3 nm and possessed a dense microstructure, which are ascribed to the high energy of the condensing species in FCVA. It was shown that the Ta filling of the trenches (0.33 mum wide, 1 : 1 aspect ratio) was very conformal and quite uniform. Also, it was preliminarily found that at the Ta film was effective against diffusion of Cu into Si at 600degreesC. [References: 21]