EVALUATION OF (ETA(5)-C5H5)(CO)NI-IN[(CH2)(3)N(CH3)(2)](2) AS A SINGLE-MOLECULE PRECURSOR FOR OMCVD OF BINARY NI/IN ALLOYS - DEPOSITION OF PHASE-PURE POLYCRYSTALLINE EPSILON-NIIN

The volatile heterodinuclear organometallic compound (eta(5)-C5H5)(CO)Ni-In[(CH2)(3)N(CH3)(2)](2) (1) has been shown to serve as a single-molecule precursor to deposit Ni/In alloy thin films by thermal chemical vapor deposition using either a horizontal hot-wall reactor in the absence of carrier gases in vacuo or a vertical cold-wall reactor with the carrier gases N-2 and H-2. The metal ratios of the thin films depend on the substrate temperature. Nickel rich films were deposited below 250 degrees C. The 1:1 stoichiometry of the metals of the precursor compound is perfectly retained above 350 degrees C. Typical growth rates were between 0.1 and 3 Angstrom s(-1). At low substrate temperatures the cyclopentadienyl ligand is transferred from the nickel atom to the indium center during the film growth generating volatile and thermally stable [(eta(5)C(5)H(5))In] which leaves the reaction zone. Other byproducts were mainly cyclopentadiene and unsaturated dimethylpropylamines, e.g., H2C=CHCH(2)NMe(2). The films were examined by SEM-EDX and Auger electron spectroscopy and proved to be reasonably pure showing levels of C, O, and N below 1-2 atom % and exhibit specific resistivities in the range of 250(+50) mu Omega cm. Films grown on various substrates (quartz, GaAs, InP) were structurally characterized by X-ray diffraction showing the hexagonal epsilon-NiIn as the only detectable crystalline phase. Plasma enhanced MOCVD experiments were also performed and expectedly showed a much lower selectivity of the decomposition chemistry of the precursor. Ni/In microstructures (e.g., squares of 200 mu m side length, a line width of 25 mu m and a line height of 12 mu m) were drawn by photothermic laser direct writing on Al2O3 substrates.