SiOpitoisuus

SiOpitoisuus refers to the concentration of silicon monoxide (SiO) and related suboxide species within a silicon-containing material, typically expressed as a ratio of SiO-related content to the total silicon-oxygen content. In practice, many silicon oxide films are non-stoichiometric, described as SiOx with 1 ≤ x ≤ 2; x = 2 corresponds to SiO2, while lower values indicate higher SiO content.

SiOpitoisuus arises during processes such as chemical vapor deposition, sputtering, thermal oxidation, or annealing under limited oxygen supply, where incomplete oxidation or transient SiO formation can occur. It also depends on temperature, oxygen partial pressure, deposition rate, and the presence of reducing species.

Measuring SiOpitoisuus employs techniques such as X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), Fourier-transform infrared spectroscopy (FTIR), ellipsometry, and, in some cases, thermogravimetric analysis (TGA). Data are interpreted in terms of oxide stoichiometry, bonding states, or oxide thickness with suboxide models.

Impact and control: Higher SiO content affects optical properties (lower refractive index, presence of absorption bands), electrical properties (trap densities, leakage currents in dielectrics), and mechanical properties (film stress and density). In device fabrication, controlling SiOpitoisuus is achieved by adjusting oxygen partial pressure, substrate temperature, deposition rate, and post-deposition annealing.

See also: Silicon dioxide, silicon oxide suboxide (SiOx), thin-film deposition.