The continuing innovation of consumer electronics requires smaller and smaller computer chips to increase speed and storage. For decades the core of these chips has been a thin film of silicon dioxide. As computer chips got smaller, less material was used to the point where it was only a few atoms thick. Electrons could leak through and cause poor performance. A new material with a higher dielectric constant (k) that would stop leakage was needed. After at least a decade of work, the industry adopted a new material, namely hafnium dioxide. Chip leader Intel calls this “the biggest change in 40 years.”

Such a small change was a huge undertaking. Chemical vapor deposition (CVD) or atomic layer deposition (ALD) would be required to grow or deposit the thin film of hafnium dioxide. For these techniques to work, a suitable chemical precursor containing hafnium needed to be identified. The precursor needed the right balance of properties (e.g., volatility, reactivity, stability, purity, and cost). The films produced from the precursor also needed the right blend of properties such as adhesion, growth rate, and smoothness. Praxair's R&D team identified the most promising candidates using specially designed inert atmosphere thermo gravimetric analysis and vapor phase thermal stability equipment. The team developed the class of compounds called hafnium dialkylamides. Tetrakis(dimethylamino)hafnium, or TDMAH, is an example of this type of molecule.

Praxair has developed a patented process for a large scale production of ultra-high purity hafnium precursors, and a systematic method for assuring packaging integrity (many precursors are highly sensitive to air and moisture). These processes have been used to commercialize hafnium dialkylamide products that are now being produced in metric ton quantities and sold worldwide for millions of dollars.