Effect of ion bombardment during chemical vapor deposition of TiN films

Abstract

Titanium nitride (TiN) Rims were deposited using tetrakis(dimethylamido)titanium (TDMAT) as a precursor. During Rim growth, N- and Ar-ion beams with an energy of 120 eV were supplied in order to improve the film quality. The films deposited using a N-ion beam showed a resistivity of about 320 mu Omega,cm and density of 4 g/cm(3). The use of the N-ion beam, however, drastically degraded the step coverage of the film (below 5% at the 0.5 x 1.5 mu m contact). The films deposited using an Ar-ion beam showed a resistivity of about 800 mu Omega cm and density of 3.2 g/cm(3). The step coverage measured at the same contact was around 30%. For comparison, the thermally decomposed film showed a resistivity of about 5800 mu Omega cm and density of 2.5 g/cm(3). Finally, the diffusion barrier properties of 50 nm thick TiN films for Cu were investigated by the etch-pit test. The films deposited using N- and Ar-ion beam failed after annealing at 600 and 650 degrees C for 1 h, respectively, while thermally decomposed films failed at temperatures as low as 500 degrees C. It is thought that the improvements of the diffusion barrier performance of the films deposited using a N- and Ar-ion beam are the consequence of the film densification resulting from ion bombardment during film growth. (C) 2000 The Electrochemical Society.