Heat transfer model of an iCVD reactor

Abstract

a b s t r a c t a r t i c l e i n f o Available online xxxx Keywords:Hot-wire CVD iCVD Heat transfer Contrary to conventional HWCVD, the power consumption in the iCVD process is dominated by heat conduction rather than radiation. This is due to the fact that while the typical wire temperature for HWCVD is about 1750-2200°C, for iCVD the temperature is only 250-500°C. Typical deposition pressures are in the transition regime between the collision free regime, where the conduction is pressure dependent, and the collision mediated regime, where the conduction is pressure independent. The power loss due to heat conductivities of molecular nitrogen, glycidyl methacrylate (GMA) and tert-butylperoxide (TBPO) gases have been determined experimentally for these pressure regimes. The necessary power input to the filaments can be explained to be due to mainly heat dissipation by radiation and by gas conduction. This means that the dissociation process requires only very little power, about 2% of the total power consumption in a typical iCVD process.

Carburization of Tungsten Filaments in a Hot-Wire Chemical Vapor Deposition Process using 1,1,3,3-Tetramethyl-1,3-disilacyclobutane

“…During the 1 h filament carburization process, constant filament temperatures were maintained by adjusting the dc power supplied to the filament. Recently, there has been increasing interest in understanding the power consumption in the HWCVD process ,,,− . The power consumed is now well described by eq .…”

Applications of soft biomaterials based on organic and hybrid thin films deposited from the vapor phase

“…The plasma in PECVD is defined by several parameters, such as the power density, the gas type, flowrate, pressure and the employed plasma power, which, together with the geometry of the reactor, influence the properties of the coating. Low-energy plasmas are typically generated using radio frequencies, whereas high energy plasmas are generated by inductively coupled and electron cyclotron resonance plasmas [20]. To start a PECVD process, a vacuum chamber is first fed with the reactive gases and vapors.…”

Synthesis and Investigation of a Photoswitchable Copolymer Deposited via Initiated Chemical Vapor Deposition for Application in Organic Smart Surfaces

“…The iCVD method is based on a radical polymerization reaction where the used monomer and the initiator species are led over a hot filament, which is placed parallel to a cooled sample stage. While the monomer species simply pass through the filaments and adsorb onto the substrate, the initiator thermally decomposes and forms free radicals that start the polymerization reaction directly on the surface of the material to be coated. − Due to the full preservation of chemical groups of the used precursors, functional polymer coatings such as hydrogels for controlled drug release applications, fluoropolymers for utilization as electret layers, and superhydrophobic coatings are possible. − Hydrogel thin films based on hydroxyethyl methacrylate (HEMA) are of great interest in biomedical applications, as well as in controlled drug release, where these materials stand out for their biocompatibility. Synthesis via iCVD allows for the variation of the cross-linking degree to significantly modify the drug release rate of the functional thin film, without retention of solvents that are necessary in common wet chemistry approaches. , Though concepts of photoactive thin films and combining photoswitchable molecules with hydrogels in the context of iCVD have been reported, , we were the first to demonstrate the simultaneous copolymerization of a functional chromophore within the iCVD process without the need for postreactional treatment .…”