Optical characterization of TiN/SiO2(1000 nm)/Si system by spectroscopic ellipsometry and reflectometry

Titanium nitride (TiN) films are used as diffusion barrier layers in the se miconductor industry. There is a need for accurate data on optical properti es, because film thickness are usually monitored by optical methods. There are further needs to characterize TiN/(interlayer dielectrics)/Si system si multaneously. Thus, TiN(35, 60, 90 and 105 nm)/SiO2(1000 nm)/Si samples wer e prepared using sputtering from a TiN target in argon and nitrogen atmosph ere. Those samples were characterized using simultaneous fits of multiple a ngle of incidence spectroscopic ellipsometry and normal incidence spectrosc opic reflectivity. TiN films partially transmit light that interferes in th e thick thermal silicon oxide, which gives more detailed information on the optical properties of TIN. Consequently optical dielectric function of TiN as well as two thickness of TIN and SiO2 were successfully determined simu ltaneously. (C) 2001 Elsevier Science B.V. All rights reserved.