Tantalum nitride properties

Electrical Properties. Electrical properties are important for the corrosion protection of chip-on-board (COB) encapsulated devices. Accelerated temperature, humidity, and bias (THB) are usually used to test the embedding materials. Conventional accelerating testing is done at 85°C, 85% relative humidity, and d-c bias voltage. Triple-track test devices with tantalum nitride (Ta2N), titanium—palladium—gold (Ti—Pd—Au) metallizations with 76... 

Tantalum, properties of. SeeTransition metals Tantalum nitride, 453... 

Table 11.11 Characteristics and Properties of Tantalum Nitride. Note Unless otherwise stated, test temperature is 20°C and quoted properties are those of the mononitride.

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. 

Corrosion of the plates not only detracts from their mechanical properties but also gives rise to undesirable corrosion products, namely, heavy-metal ions, which, when depositing on the catalysts, strongly depress their activity. The corrosion processes also give rise to superficial oxide films on the metal parts, and these cause contact resistance of the surfaces. For a lower contact resistance, metallic bipolar plates sometimes have a surface layer of a more stable metal. Thus, in the first polymer electrolyte membrane fuel cell, developed by General Electric for the Gemini spacecraft, the bipolar plates consisted of niobium and tantalum coated with a thin layer of gold. A bipolar plate could also be coated with a layer of carbide or nitride. 

This chapter is a review of the properties and general characteristics of the interstitial nitrides formed by the metals of Group IV (titanium, zirconium, and hafiiium) and Group V (vanadiiun, niobium, and tantalum). As mentioned in Ch. 10, these six nitrides are the only refiactory transition-metal nitrides. Th have similar properties and characteristics and, of the six, titanium nitride has the greatest importance from an application standpoint. 

Gerasimov et have provided a reference book on the thermodynamic properties of tungsten, molybdenum, titanium, zirconium, niobium, and tantalum, and their more important compounds, viz. oxides, sulphides, halides, carbides, nitrides, silicates, borides, and hydrides. 

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