Detailed Kinetic Modeling of Silicon Nanoparticle Formation Chemistry via Automated Mechanism Generation

Abstract

Thermal decomposition of silane can be used to produce silicon nanoparticles, which have attracted great interest in recent years because of their novel optical and electronic properties. However, these silicon nanoparticles are also an important source of particulate contamination leading to yield loss in conventional semiconductor processing. In both cases, a fundamental knowledge of the reaction kinetics of particle formation is needed to understand and control the nucleation of silicon particles. In this work, detailed kinetic modeling of silicon nanoparticle formation chemistry was carried out using automated reaction mechanism generation. Literature values, linear free-energy relationships (LFERs), and a group additivity approach were incorporated to specify the rate parameters and thermochemical properties of the species in the system. New criteria for terminating the mechanisms generated were also developed and compared, and their suitability for handling an unbounded system was evaluated. Four different reaction conditions were analyzed, and the models predicted that the critical particle sizes were Si 5 for an initial H 2 /SiH 4 molar ratio of 90:10 at 1023 K and Si 4 for the same initial composition at 1200 K. For an initial H 2 /SiH 4 molar ratio of 99:1, the critical particle size was larger than or equal to Si 7 for both temperatures, but it was not possible to determine the exact critical particle size because of limitations in computational resources. Finally, the reaction pathways leading to the formation of nanoparticles up to the critical size were analyzed, and the important species in the pathways were elucidated.

Identification of higher order silanes during monosilane pyrolysis using gas chromatography-mass spectrometry

“…Our observation is in line with results by Wong et al [27], who have modelled silicon nanoparticle formation via automated mechanism generation. At a simulated reactor temperature 750°C and an initial concentration of 10% SiH 4 in H 2 , these authors report cyclopentasilane to be the most abundant pentasilane species.…”

“…[13][14][15][16][17][18][19][20] and by modelling [see e.g. 13,16,[20][21][22][23][24][25][26][27], have been conducted to broaden the understanding of the monosilane pyrolysis. It is commonly accepted that the pyrolysis occurs through a series of chemical reactions, including SiASi bond formation and hydrogen elimination, producing silanes with increasing number of Si atoms [13,20,22,23,28,29].…”

“…Additionally, 1,2-hydrogen shifts, ring opening and ring closing lead to interconversion between different isomers within each silane family [22,23,30,31]. Many of the kinetic models of the monosilane pyrolysis process have an impressive degree of detail, some of which include hundreds of species with up to 10 Si atoms and more than one thousand chemical reactions [16,[21][22][23]27]. The experimental works in the field, on the other hand, have a much lower degree of detail.…”

Computational Modeling of Silicon Nanoparticle Synthesis: II. A Two-Dimensional Bivariate Model for Silicon Nanoparticle Synthesis in a Laser-Driven Reactor Including Finite-Rate Coalescence

“…Numerous studies of silane decomposition kinetics have been reported (Becerra and Walsh 1992;Ho et al 1994;Moffat et al 1992a, b;Purnell and Walsh 1984;Wong et al 2004). As in Dang and Swihart (2008), this work used an extensive chemical kinetic mechanism for silicon hydride cluster formation during silane pyrolysis (Swihart and Girshick 1999).…”

A Review of Kinetic Modeling Methodologies for Complex Processes

“…-coke formation (Moustafa and Froment, 2003;QuintanaSolórzano et al, 2005), -biomass conversion (Rangarajan et al, 2010), -oxidative coupling of methane (Simon et al, 2007), -silicon hydride clustering (Wong et al, 2004), -hydrocarboxylation , -carbonylation (Bruk et al, 1998), -organic synthesis (Fontain and Reitsam, 1991), -biological processes (Valdes-Perez, 1992b;Klein et al, 2002;Faeder et al, 2003Faeder et al, , 2005Li et al, 2004;Hatzimanikatis et al, 2004Hatzimanikatis et al, , 2005Blinov et al, 2005a, b;Mayeno et al, 2005;Henry et al, 2007Henry et al, , 2010Hill et al, 2008;Finley et al, 2009), -and many more.…”