Low temperature (<700 °C) SiO2 and Si-rich SiO2 films: Short review

SiO2 layers deposited at temperatures (lower than 700 °C) have attracted a great deal of attention for a large variety of applications, since they can be used for dielectric isolation, a needed approach for multilayer, multifunctional coatings that exhibit two or more properties simultaneously. A similar phenomenon occurred with Si-rich SiO2, a two-phase material in which excess silicon, introduced during the deposition process of the films, forms a Si inclusion phase uniformly embedded in a SiO2 matrix, modifying its optical and electrical characteristics. In this short review, the synthesis methods to obtain high electronic quality SiO2 deposited films at low temperatures, as well as Si-rich SiO2 films (mainly the chemical vapor deposition technique in different versions), precursor materials, and characteristic properties, will be described together with some of their applications, beyond integrated circuit technology, that have become relevant in recent times. This is the case of solar filters, antireflecting coatings for solar cell panels, light emitting devices or liquid crystal displays, and bioimaging and theranostic applications.