Séminaire exceptionnel – 6 jan. 2017 – 11h salle 250

Measuring the vapor pressure of a difficult sample

Robert Berg – NIST Gaithersburg, ÉU

Microprocessor manufacturers often use a metal-organic vapor to create, for example, copper lines or hafnium oxide dielectric layers. Operating the vapor delivery device requires knowledge of the compound’s vapor pressure, and the most accurate way to obtain that knowledge is also the simplest: Attach a pressure gauge to a container of the compound and wait for pressure equilibrium. But… what if the compound is decomposing and equilibrium never happens? I will give various reasons why so-called “static” vapor pressure measurements can actually be time dependent. Then I will show how simple assumptions about decomposition and diffusion lead to a model that yields the right answer even when the partial pressure of the decomposition product is larger than the vapor pressure of the original compound.