Tantalum nitride, TaN

Tantalum nitride (TaN) from the metal chloride reaction with nitrogen at 800-1500°C. 

Tantalum Nitride as Diffusion Barrier. Tantalum nitride (TaN) produced by MOCVD has excellent potential as a barrier material, comparable to TiN. The resistivity of TaN thin films can be lowered by rapid thermal annealing in nitrogen. 

The functional phase in thick-film resistors is a mixture of electrically conducting (or semiconducting) ceramic powders such as ruthenium dioxide (RUO2), bismuth ruthenate (Bi2Ru207), lead ruthenate (Pb2Ru206), and Ag-Pd-PdO mixtures for use in air-fired pastes and tantalum nitride (TaN) for nitrogen-fired pastes. The resistance of thick-film resistors is specified in terms of sheet resistance, which has units of ohms/square (Q/D). 

Tantalum (Ta) and tantalum nitride (TaN) are particularly suitable materials for use in the damascene process as adhesion-promoting and/or diffusion barrier layers for copper-based devices. However, the properties of Ta and of TaN differ from those of copper, being considerably more chemically inert, such that abrasive-free polishing compositions useful for the polishing of copper are often unsuitable for the removal of underlying Ta and TaN. Hence, independent chemistries are often developed to clear Ta/TaN without further dishing of interconnect metal (Cu) or dielectric loss. 

The most common types of resistor material are nichrome (NiCr) and tantalum nitride (TaN). Although NiCr has excellent stability and TCR characteristics, it is susceptible to corrosion by moisture if not passivated by sputtered quartz or by evaporated silicon monoxide (SiO). TaN, on the other hand, may be passivated by simply baking in air for a few minutes. This feature has resulted in the increased use of TaN at the expense of NiCr, especially in military programs. The stabihty of passivated TaN is comparable to that of passivated NiCr, but the TCR is not as good unless annealed for several hours in a vacuum to minimize the effect of the grain boundaries. Both NiCr and TaN have a relatively low maximum sheet resistivity on alumina, about 400 S2/ for NiCr and 200 / for TaN. This requires lengthy and complex patterns to... 

Tabor relationship, 13, 238-239 Tantalum nitride (TaN), cubic, hardness, 297... 

Thin-fikn circuits typically consist of three layers of material deposited on a substrate. The bottom layer serves two purposes It is the resistor material and it also provides the adhesion to the substrate. The adhesion mechanism of the film to the substrate is an oxide layer that forms at the interface between the two. The bottom layer must therefore be a material that oxidizes readily. The most common types of resistor material are nichrome (NiCr) and tantalum nitride (TaN). Gold and silver, for example, are noble metals and do not adhere well to ceramic surfaces. 

In the case of nitrogen firing, typical conductive phases are tin oxide (SnOj), indium oxide (lUjOj), strontium ruthenate (SrRuOj), lanthanum hexaboride (LaBg), titanium disili-cide (TiSij), and tantalum nitride (TaN). 

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