Role of spinodal decomposition in the structure ofSiOx

Silicon Oxide (SiOx, 0&ltx&lt2): a Challenging Material for Optoelectronics

“…Based on calculations of the Gibbs free energy (Hamann, 2000) it was shown that tetrahedra as Si-(Si 4 ) and Si-(O 4 ) are stable, while Si-(Si n O 4-n ), with n=1, 2, 3 are in-or unstable. From a thermodynamics point of view the latter structures can change into a stable configuration via spinodal decomposition (van Hapert et al, 2004). The most unfavorable structural entity is Si-(Si 2 O 2 ); the chemical bond between the central silicon atom and the oxygen ones is much stressed (disturbed) and, if conditions for migration of an oxygen atom are satisfied, the so called phase decomposition will take place.…”

Resolving the nanostructure of plasma-enhanced chemical vapor deposited nanocrystalline SiOx layers for application in solar cells

“…13 For several years, spinodal decomposition of a-SiO x layers by thermal annealing was used to fabricate silicon nanocrystals (nc-Si) in a silicon-dioxide matrix. [14][15][16][17] Moreover, the ability to control the size of the silicon nanocrystals in a silicon-dioxide matrix is indispensable in the study of quantum confinement effects. 14 Finally, nc-SiO x is not only a versatile model system for studying quantum-dot networks but also a candidate material for silicon-based light-emitting diodes.…”

On the argon and oxygen incorporation into SiOx through ion implantation during reactive plasma magnetron sputter deposition

“…We tend to ascribe the variation in argon concentration for varying values of x in SiO x to a shift in the equilibrium between implantation and desorption [12]. It is conceivable that the SiO 2 -type of network, or the boundaries between the SiO 2 rich and O-poor regions, existing because of the spinodal decomposition in the SiO x films [11], offer fast diffusion paths for argon stimulating a more readily desorption of subsurface implanted argon, resulting in a lower built-in argon concentration. Another explanation is the possible participation of silicon-rich regions in the stabilization of the implanted argon, as suggested by recent theoretical work on SiBCN materials [22]: the contribution of Si-rich regions to the suboxide network decreases with increasing x-value, and there are simply no silicon rich regions for x = 2.…”

“…The deposited SiO x films are amorphous and show a tendency to separate in nanoscale oxygen-poor and oxygen-rich regions as a result of spinodal decomposition [11,14].…”

“…For an argon plasma the main constituents of the bombarding ion flux are Ar + ions. The concentration of argon incorporated in the growing film can be appreciable [10][11][12] and may depend on the negative bias of the growing film [12,13]. For an O 2 containing plasma O 2 + , O + and SiO + ion bombardment may contribute to the oxygen incorporation in the growing film [3], and is expected to be especially noticeable in those cases where the incorporation probability of neutral molecular oxygen is low.…”