Cr-based MOCVD layers as conducting diffusion barriers for copper metallization

Two types of amorphous Cr-based thin films, CrCxNy and CrSixCy, were grown by low pressure MOCVD on Si substrates using respectively Cr(NEt2)4 and Cr[CH2SiMe3]4 as single-source precursor in the low temperature range 400-420 °C and 475-500 °C. Their properties as conducting diffusion barrier against Cu were investigated and the results are discussed. CrSixCy exhibits a better thermal stability and a good Cu wettability but a high resistivity, which is detrimental for this application. CrCxNy has a low resistivity, a satisfactory stability up to 650 °C without undesirable interfacial reactions and an excellent conformality.Two types of amorphous Cr-based thin films, CrCxNy and CrSixCy, were grown by low pressure MOCVD on Si substrates using respectively Cr(NEt2)4 and Cr[CH2SiMe3]4 as single-source precursor in the low temperature range 400-420 °C and 475-500 °C. Their properties as conducting diffusion barrier against Cu were investigated and the results are discussed. CrSixCy exhibits a better thermal stability and a good Cu wettability but a high resistivity, which is detrimental for this application. CrCxNy has a low resistivity, a satisfactory stability up to 650 °C without undesirable interfacial reactions and an excellent conformality

Real time monitoring of the growth of metallic thin films by in situ pyrometry

In situ temperature measurement is an integral part of deposition processes and optical pyrometry is a useful technique to control the temperature of the growing film. In this work, in situ IR pyrometry has been used for real time monitoring of the early stages of the growth of metallic type thin films selected as model system. Significant variations of the pyrometric signal were observed during MOCVD of CrC$\rm _x$N$\rm _y$ films due to changes of emissivity of the film/substrate system. The pyrometric signal (or emissivity) depends predominantly on the nature, the thickness and the surface roughness of the growing film. As a result, fruitful informations as the formation of an interphase or the existence of an induction period can be obtained in real time by this technique. IR pyrometry can be used as surface diagnostic tool for a large variety of thin film materials that exhibits an emissivity sufficiently different from the substrate.

Fracture and fatigue properties of metallic alloys S275 J2 and Al7075 T6 at low temperatures.

Knowledge of the fracture and fatigue behaviour of metallic alloys at extreme environmental temperature conditions is required to assess the safety of structural components operating in particular fields: aero-spatial, off-shore structures, power plants superconductors, polar Antarctic facilities, etc. Among the structural metallic alloys for civil, mechanical engineering and plant applications, steel S275 J2 is widely used, whereas aluminium alloys such as Al7075 T6 are significant especially for aero-spatial and polar Antarctic applications. In this paper, the main experimental mechanical characteristics of such metallic materials at room temperature as well as at low temperatures are examined. Three temperatures are considered: 293 K (+20 °C, room temperature RT), 243 K (−30 °C) and 193 K (−80 °C). The corresponding values of fracture toughness and endurance limit available in the literature are reported herein. Further, experimental tests have been performed to determine the unavailable mechanical properties. Then, the values of such fracture and fatigue parameters at various temperatures are critically discussed