Formation and characteristics of silicon nanocrystals in plasma-enhanced chemical-vapor-deposited silicon-rich oxide

Abstract

Articles you may be interested inMethods of producing plasma enhanced chemical vapor deposition silicon nitride thin films with high compressive and tensile stress J. Vac. Sci. Technol. A 26, 517 (2008); 10.1116/1.2906259 Silicon nanocrystal formation in annealed silicon-rich silicon oxide films prepared by plasma enhanced chemical vapor deposition A comparative study on inductively-coupled plasma high-density plasma, plasma-enhanced, and low pressure chemical vapor deposition silicon nitride filmsThe formation of nanosized Si crystals in dual-frequency plasma-enhanced chemical-vapor-deposited silicon oxides is identified in this study. As a higher SiH 4 N 2 O gas flow rate ratio is employed during the deposition process, the silicon-to-oxygen atomic ratio and the dangling bond density both increase. The resulting oxide films contain more Si-H bonds and less Si-O and Si-O-H bonds, as determined from the Fourier-transform infrared spectra. The main type of charge defects in these oxides change from "SiwO 3 bonds (EЈ centers͒ to "SiwSi 3 bonds, which eventually cluster together and precipitate out from the oxide network to form the Si nanocrystals. The size of these Si nanocrystals falls within the range of 30-50 nm, as observed by high-resolution transmission electron microscopy. The formation of these nanocrystals inside the silicon-rich oxides results in a lower film density, a tensile stress component, and a higher wet etching rate, even under the ion bombardment provided by the rf bias power during deposition. The underlying mechanisms for the formation of these Si nanocrystals from the silicon oxide will be proposed.

XPS study of ion‐beam‐assisted formation of Si nanostructures in thin SiO2 layers

“…9 -11,13 The formation of Si nanocrystals embedded in SiO 2 was claimed when the substrate temperatures during deposition exceeded 400°C. 9,10,13 However, deposition of co-sputtered Si and SiO 2 without intentional heating of the substrates does not lead to the appearance of nanocrystals in the as-prepared layers. 11 One can conclude that crystallization is provided by a combination of thermal and ion-induced processes.…”

Light emission from nanocrystalline silicon clusters embedded in silicon dioxide: Role of the suboxide states

“…The silicon nanocrystals can be produced by annealing silicon oxide supersaturated with excess silicon atoms, either introduced during growth by sputtering [13,14], chemical vapor deposition [15,16], laser ablation [17], or by ion implantation [18,19]. The latter method is routinely used in silicon integrated circuit technology and offers a number of advantages such as high controllability of dopant concentration and spatial distribution, as well as the possibility of extending elemental clusters forming compounds using sequential implantation of different ions.…”

Colloidal Solutions with Silicon Nanocrystals: Structural and Optical Properties

“…Today, there are a lot of methods for obtaining silicon nanocrystals, namely Stober, pulsed laser, controlled precipitation, emulsions, oxidation, silane combustion, gas evaporation, cosputtering and thermic degradation [37][38][39][40][41][42][43][44][45][46][47][48], chemical vapor deposition (CVD) [49,50], low pressure chemical vapor deposition (LPCVD) [51], ionic implantation [52,53] and other ones. Unfortunately, such methods are very expensive.…”