2. The unavoidable presence of metals

We often speak of the "age of silicon". Yet metals are present at every level of microelectronics. Indeed, an electronic component must transport electrons: this is the function of interconnections made of high-purity metals with excellent electrical conductivity. In doing so, it generates heat which must be dissipated; circuit supports fulfill this function, with metal matrix composites taking the lion's share. The characteristic of an electronic circuit is to be spatially architected from the point of view of its chemistry: diffusion barriers must be put in place, often consisting of intermetallics. Transistor gates are formed from complex stacks of metals and high-dielectric-constant materials, replacing polycrystalline silicon and gate oxide. Here are a few examples of situations in which metallic materials are indispensable, and let's take a look at some behavioral problems specific...