Precursor chemistry and film growth with (methylcyclopentadienyl) (1,5-cyclooctadiene)iridium

We have investigated the chemistry of the iridium precursor ((methylcyclope ntadienyl) (1,5-cyclooctadiene))iridium (MeCpIrCOD) and have utilized the p recursor for chemical vapor deposition (CVD) of iridium films. The vapor pr essure of the precursor is similar to 80 and similar to 280 mTorr at 80 and 120 degrees C, respectively. The precursor slowly dimerized at elevated te mperatures (>60 degrees C). Pyrolysis studies revealed that the compound de composes by breaking the methylcyclopentadienyl-Ir and cyclooctadiene-Ir bo nds nearly simultaneously at temperatures above 400 degrees C. Iridium film s grown at substrate temperatures between 250 and 400 degrees C were charac terized by in situ x-ray photoelectron spectroscopy, x-ray diffraction, and scanning electron microscopy. Pure CVD iridium films were obtained on vari ous substrates by codosing MeCpIrCOD with oxygen or hydrogen. Without oxyge n, the metal films required higher growth temperatures and contain similar to 87% carbon. Oxygen also affected the film deposition rate and lowered gr owth temperature. X-ray diffraction analysis indicated that films grown bel ow 270 degrees C are randomly oriented, while films grown at 350 degrees C favor the (200) orientation. Excellent step coverage has been achieved on S i3N4 and other substrates. The effective activation energy for Ir film grow th, with oxygen present, is 71 kJ/mol. (C) 2000 American Vacuum Society. [S 0734-2101(00)04501-2].