Detection of Si nanoclusters by x-ray scattering during silicon film deposition by mesoplasma chemical vapor deposition

Abstract

A laboratory-scale small angle x-ray scattering (SAXS) system was designed to detect free silicon nanoclusters generated in the gas phase during silicon film deposition by an inductively coupled mesoplasma chemical vapor deposition system at different SiH4 partial pressures and rf powers. Analysis of the SAXS profiles collected from the vicinity of the plasma-substrate boundary layer has revealed the presence of a polydisperse system of spherical scatterers having a loosely bound structure with around 2–3nm in size. A small amount of larger-sized nanoclusters was found to form as the rf power decreased, and emergence of such large nanoclusters was seen to be associated with the transition from an epitaxial to agglomerated microstructure of the films so deposited.

Size distribution and surface characteristics of silicon nanoparticles

“…Since the late 1990s SAXS has been used to study the formation of semiconductor nanoparticles through wet chemical synthesis (Mattoussi et al, 1998;Tokumoto et al, 1999). More recently, methods have been developed to study in situ the formation of nanoparticles during flame pyrolysis to produce silica (Kammler et al, 2004) and plasma-enhanced chemical vapour deposition of silicon (Diaz et al, 2008). However, for silicon, most small-angle scattering studies over the past two decades have focused on porous silicon (e.g.…”

High-rate and wide-area deposition of epitaxial Si films by mesoplasma chemical vapor deposition

“…The high quality of MPCVD films resulted in a Hall mobility of about 70% of that of the p-type Si wafer [5]. It is considered that the simultaneous attainment of these characteristics is attributed to its unique deposition process, which includes the formation of nanoclusters as deposition precursors and the high degree of non-equilibrium during epitaxial growth [6]. When one considers the large area deposition with MPCVD, either plasma torch or substrate needs to be swept because the unique characteristics descried above are primarily attained by the plasma flow with inductively coupled plasma (ICP).…”

Enhanced Deposition Efficiency of Epitaxial Si Film from SiHCl3 by Mesoplasma Chemical Vapor Deposition

“…The mesoplasma CVD process [4][5][6], which was developed originally based on the plasma spray CVD [7], provides a fast-rate Si epitaxy. In this process, the source gases are decomposed completely in the core plasma and the Si vapor is transported toward the substrate and condensed into nano-clusters within the confined thermal boundary layer present ahead of the substrate.…”

“…In this process, the source gases are decomposed completely in the core plasma and the Si vapor is transported toward the substrate and condensed into nano-clusters within the confined thermal boundary layer present ahead of the substrate. These nano-clusters are identified to be globular and loosely bound structure [5] and their unique self-ordering and spreading dynamics are considered to be the central factor for the fast rate epitaxy under high number density condition [8]. It is also expected to provide a high-atomic-hydrogen environment where Si-Cl related species could be less stable, so that more Si vapor can get involved into deposition.…”