Growth rate and microstructure of copper thin films deposited with metal-organic chemical vapor deposition from hexafluoroacetylacetonate copper(I) allyltrimethylsilane

Abstract

Metal-organic chemical vapor deposition of copper using the copper(I) compound, (hfac)Cu(ATMS) (hfac = hexafluoroacetylacetonate, ATMS = allyltrimethylsilane) as a precursor, was carried out on TiN surface over a substrate temperature range of 60 similar to 275 degrees C. It was found that the deposition temperature could be substantially lower compared with (hfac)Cu(VTMS) (VTMS = vinyltrimethylsilane). In the substrate temperatures ranging from 60 to 90 degrees C, the Arrhenius plot showed a reaction-rate-limited regime with an activation energy of 15.0 kcal/mol. Above 90 degrees C, the deposition rate showed a feed-rate-limited regime with an activation energy of 0.1 kcal/mol. The copper films contained no detectable impurities by Auger electron spectroscopy and gave resistivities below 2.0 mu Omega cm in the temperature range of 125 similar to 170 degrees C. As substrate temperature increased, the small-grained, smooth and continuous film structure changed to large-grained and rough film structure that was poorly connected and resulted in high resistivities. The polycrystalline phases with a preferred orientation of (111) and loss of selectivity were observed over a wide range of substrate temperatures. (C) 1998 Elsevier Science S.A. All rights reserved.