EVALUATION OF TETRA-ALKYLCHROMIUM PRECURSORS FOR ORGANOMETALLIC CHEMICAL VAPOR-DEPOSITION .1. FILMS GROWN USING CR[CH2C(CH3)3]4

Chromium carbide thin films have been deposited by organometallic chemical vapour deposition using the sigma-alkylchromium complex Cr[CH2C(CH3)3]4. The growth was achieved in a hot wall, low pressure chemical vapour deposition reactor in the temperature range 250-350-degrees-C under an inert or hydrogen atmosphere. As a result of the high reactivity of this precursor towards oxygen, the films were partially oxidized. Oxygen incorporation decreases on increasing the deposition temperature. Characterization of their heterogeneous structure, mainly by electron diffraction and X-ray photoelectron spectroscopy, gives evidence, in spite of a poor crystallinity, for a mixture of cubic chromium carbide CrC1-x phase, amorphous chromium metal, chromium oxides (mainly Cr2O3) and free carbon, whose proportions depend on the deposition conditions.