Silicon oxidation is the exposure of silicon (or polysilicon) to the action of gas oxidants (O2- termed dry oxidation, H2O – termed wet oxidation) at high temperatures (800-1150C). It is usually an atmospheric pressure process run on large tubular furnaces holding up to several tens of substrates. Part of the silicon of the surface (layer) is consumed and transformed in SiO2 so the starting thickness of the silicon layer is reduced (roughly 50% of the thickness of the obtained silicon dioxide); it can be used for thinning silicon micro-nanostructures. Oxide thicknesses of a few nanometers to two micron can be obtained depending on the temperature, time and ambient of the oxidation process. Dry oxidation is best suited for thin oxides and wet oxidation is best suited for thicker ones.
Diffusion is the process by which a species moves in a given environment due to a spatial gradient in concentration. Diffusion processes in the field of microelectronics are those that allow the spatial and in-depth definition of the substrate regions with different dopant species (mainly, boron and phosphorus) that are in the base the semiconductor industry. Depending on the depth pursued high temperatures and long times may be needed.
An annealing is a thermal process in which the substrates are exposed to different temperatures, times and environments depending on the pursued objective such as the predeposition of doping species (as an alternative to ion implantation), the post-implant annealing for impurities activation, the fluidization of interlevel dielectric layers, annealing of aluminum layers for contacts formation and the densification of different deposited layers.
RIE is used to etch various materials under vacuum in the presence of reactive ions. The sample to be etched is placed in a vacuum chamber and gas is injected into the process chamber via a gas inlet in the top electrode. The lower electrode is negatively biased and a single RF plasma source determines both the ion density and their energy.
Ultraviolet lithography also known as optical or photolithography is the most commonly used patterning technique in microfabrication. A photosensitive material (photoresist) is spin-coated onto the substrate to be patterned. The photoresist is illuminated with UV light through a photomask which contains the relevant geometric patterns.
A set of classical microelectronic processes for deposition, of ancillary materials that are co-adjuvant to the obtention in the micro or nano domain of the functional materials that are the object of the Growth and Synthesis installation. It includes LPCVD and PECVD layers deposition or deposition of metal layers by PVD.
XPS is a surface spectroscopic technique for quantitative measurements of the elemental composition or stoichiometry and the chemical state of the present elements, like their oxidation state and chemical bonds. XPS is highly surface sensitive, giving chemical and binding energy information from the a narrow region close to the surface.
A set of classical microelectronic processes for pattern transfer through etching of thin films than are co-adjuvant to the functional materials of a given sytem under study in the micro or nano domain. It includes wet and dry etching of all those ancillary dielecric or conducting materials.