Silicon Carbide Films by Laser Pyrolysis of Polycarbosilane

Abstract

Thin films of polycarbosilane were deposited on Si and SiO 2 substrates. Instead of conventional oven annealing (high temperatures, inert atmosphere), laser pyrolysis was used to achieve the polymer-to-ceramic conversion. In some conditions, especially when laser radiation absorption was enhanced by depositing a carbon layer on the surface of as-deposited films or by embedding graphite particles, this processing method yielded SiC ceramic coatings, without damaging the substrate. Processing in air or low vacuum did not result in oxidized coatings, contrary to what happens for oven pyrolysis. Laser-converted films were similar to oven-heated films processed at 1000°to 1200°C.

Liquid polycarbosilane derived SiC coating on silicon (111) wafer for enhanced mechanical properties

“…A thin protective coating of SiC has found to be very effective in harsh environments [7], although there are reports that Si structures fabricated by deep reactive ion etching (DRIE) do not perform well in erosive environments [8], since SiC is a semiconductor with wide bandgap so it offers a promising coating material on silicon for MEMS application. Chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer epitaxy, molecular beam epitaxy, sputtering, or laser ablation have been successfully employed to deposit single and polycrystalline forms of SiC thin films on substrate [9][10][11][12]. Each technique has its own merits and limitations.…”

Synthesis and characterization of continuous freestanding silicon carbide films with polycarbosilane (PCS)

“…The spectra showed that the adsorption peak of Si-H in the film cured with oxidation was lower than that with irradiation. The presence of Si-H, Si-CH 2 -Si, Si-O-Si, and Si-CH 3 modes in their spectra, together with the measured stoichiometric ratios, suggested the formation of -[SiH(CH 3 …”

“…[1][2][3] SiC films could also be used as a material for the next generation of high-power, high-temperature electronic and optoelectronic devices. 4 Amorphous and polycrystalline ␤-SiC films had attracted much attention for the applications such as hard protective coatings, semiconductor, structural materials for power microelectromechanical systems (MEMS) in harsh environments.…”

“…6 So far, chemical vapor deposition (CVD), physical vapor deposition (PVD), molecular beam epitaxy, sputtering, or laser ablation have been successfully employed to deposit SiC coatings on substrates. [3][4][5][6] However, these methods, based on relatively expensive equipment and time-consuming procedures, are not always practical or cost-efficient. It has been generally reported that the formation of voids and defects are observed at the SiC/substrate interface in the initial stage of the growth, which leads to serious problems in the realization of SiC MEMS devices.…”

Polycarbosilane based UD C/SiC composites: Effect of in-situ grown SiC nano-pins on mechanical properties

“…The heating rate affects the ceramic yield and composition [34]. Heating rate, dwelling temperature and time influence the composition and microstructure of the matrix, as they affect the extent of crystallization, carbothermal reduction reactions and filler reactions occurring in the material.…”