Influence of barrier and cap layer deposition on the properties of capped and non-capped porous silicon oxide

Novel highly porous SiO2 xerogels are being developed as low dielectric constant materials. For successful integration into DAMASCENE structures, the attractive electrical properties of these materials must not degrade as further cap and barrier layers are deposited and patterned. The influence of the deposition of PECVD SiO2 cap and sputtered and MOCVD TiN barrier layers on the electrical properties of low k xerogel films was examined. FTIR was used to show that the pore surface methyl groups formed during HMDS treatment survive cap deposition. Electrical results indicate only small changes to the dielectric constant, leakage current density and field breakdown voltage after the cap was deposited. The deposition of the barrier laver was found to increase the dielectric constant of the xerogel by about 10-15% but not when the xerogel was capped first. (C) 2001 Elsevier Science B.V. All rights reserved.