A mixture of the tungsten allylimido complexes Cl(4)(RCN)W(NC(3)H(5)) (3a, R = CH(3) and 3b, R = Ph) was tested as a single-source precursor for growth of tungsten nitride (WN(x)) or carbonitride (WN(x)C(y)) thin films. Films deposited from 3a,b below 550 degrees C contained amorphous beta-WN(x)C(y), while those deposited at higher temperatures were polycrystalline. Film growth rates from 3a,b ranged from 5 to 10 A/min over a temperature range of 450-650 degrees C, and the apparent activation energy for film growth was 0.15 eV. A plot of the E(a) values for deposition from Cl(4)(RCN)W(NR') [R' = Ph, (i)Pr, allyl] against the N-C imido bond strengths for the analogous amines R'NH(2) is linear, implicating cleavage of the N-C bond as the rate-determining step in film growth. The correlation of mass spectral fragmentation patterns for Cl(4)(RCN)W(NR') with film properties such as nitrogen content supports the significance of facile N-C bond cleavage in film growth.

Diorganohydrazido(2-) complexes of tungsten (L)Cl4W(NNR2) [R2=Me2, Ph2, -(CH2)5-; L=CH3CN, pyridine] were synthesized by reacting the corresponding 1,1-diorganohydrazine with WCl6, followed by reaction with acetonitrile or pyridine. Crystallographic structure determination of (CH3CN)Cl4W(NNMe2) and (CH3CN)Cl4W(NNPh2) allows a comparison of the structural features of the diorganohydrazido(2-) functionality with varying substituents. Mass spectrometry, thermogravimetric analysis, and preliminary chemical vapor deposition experiments were performed to determine the viability of these complexes as single-source precursors for deposition of WNx and WNxCy films.

The properties of Ta–Ge–(O)N as a diffusion barrier for Cu on silicon have been investigated. Ta–Ge–(O)N was deposited on single crystal p-Si(001) by reactive sputtering. This was followed by in situ deposition of Cu. Diffusion barrier tests were conducted by subsequent annealing of individual samples in Ar atmosphere at higher temperature. The films were characterized by x-ray diffraction, Auger electron spectroscopy, and four-point probe. The results indicate that Ta–Ge–(O)N fails after annealing at 500°C for 1h compared to Ta(O)N which fails after annealing at 400°C for 1h indicating better diffusion barrier properties.

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A mixture of the tungsten allylimido complexes Cl 4 ͑RCN͒W͑NC 3 H 5 ͒ ͑1a, R = CH 3 ; 1b, R = Ph͒ was used to deposit tungsten nitride carbide ͑WN x C y ͒ films with ammonia as coreactant. Depositions were done in a chemical vapor deposition reactor at temperatures in the range of 450-750°C. The effect of ammonia on film composition, crystallinity, lattice parameter, grain size, film growth rate, and electrical resistivity was studied. Importantly, films grown at 450°C with ammonia as a coreactant were amorphous and showed a roughly five-fold increase in nitrogen content and significantly reduced oxygen levels. The films deposited below 500°C were amorphous, whereas films deposited at and above 500°C were polycrystalline. The X-ray diffraction patterns suggest that either the solid solution ␤-WN x C y or ␤-WN 0.5 and ␤-WC 0.6 coexist in the films. An Arrhenius plot yielded an apparent activation energy of 0.34 eV for growth from 1a,b and ammonia, compared to the value of 0.15 eV reported for depositions without ammonia. As anticipated, the films deposited with ammonia exhibited higher film resistivity, with the lowest film resistivity of 1.7 m⍀ cm observed for films grown at 550°C, compared to 0.29 m⍀ cm for film grown without ammonia at 450°C.