Metallurgy for silicon-based microelectronics

The mastery of materials is an essential component in the development of microelectronics. The first transistor could only be made when a semiconductor of sufficient purity (initially germanium, then silicon) was produced, using a purification technique called "zone reflow", invented... by a metallurgist. In today's context of component miniaturization, it is essential to study new processes and materials, many of which consist of metals and their derivatives. The need to develop gradients in chemical composition, which must not change over time, calls for increasingly effective diffusion barriers. The metal interconnections that carry the current must have ever-lower resistivities, which means that structural defects must be perfectly controlled. Connectivity problems require control of the entire range of welding technologies. The current densities involved and the reduction in scales make heat elimination a major challenge, requiring the development of new materials. There is no area of microelectronics materials that can do without a good knowledge of metallurgy. In this article, we confine ourselves to metallurgy for silicon-based microelectronics; we do not deal with research in the fields of optoelectronics, electromagnetics, microwaves and antennas, even though these issues are linked to those of microelectronics. The involvement of metallurgy in this industrial sector is therefore even more essential than the few examples used here might suggest.

At the end of the article, readers will find a glossary and a table of acronyms.