Low-pressure chemical vapor deposition of TaCN films by pyrolysis of ethylamido-tantalum

Thin films of Tantalum nitride (TaN) were deposited from tetra-ethylamido-tantalum (Ta (NEt₂)₄) by low-pressure chemical vapor deposition. Good-quality step coverage is achieved below 400°C, because the deposition rate is determined by the reaction rates on the surface. The film resistivity increases, however, as the substrate temperature decreases. In order to obtain the low resistivity of films deposited at lower temperatures, we have increased the amount of injected H₂ gas during the deposition. The resistivity decreases by the increase in the H₂ gas flow rate, and it is shown that a large amount of H₂ gas injection during the deposition is an effective method for obtaining both low resistivity and high-quality step coverage. The residual carbon concentration in the film is measured to be >10%, on the other hand, the concentration of N less than 1%. The microstructural investigation using transmission electron microscopy (TEM) reveals that crystalline structure of the deposited film has an amorphous phase.