One of the major problems in understanding the structure and properties of the diffusion barrier films used in microelectronics to separate metal and semiconductor materials is the fact that most of these films are amorphous. Thus, unlike in single crystalline materials, designing an appropriate cluster model for computational investigation is a very difficult task. Fortunately, one of the most useful diffusion barrier materials, titanium carbonitride has been studied extensively and it was determined that the local electronic structure likely determines its chemical properties. Thus, a small cluster model can be very useful in describing the reactivity of the following reactive sites: Ti corner atom, Ti-C bond, and Ti-N bond. According to our studies, there are no Ti-Ti adsorption sites eveilable on the surface of these films. The experimental microscopic and spectroscopic probes help us deside on the concentrations of elements and structure of the probe clusters. Probe molecules allow us to test the computational models. For example, vinyltrimethyl silane desorbs from the surface of the TiCN film at two different temperatures (622 K peak is not related to the VTMS adsorption):