Chamberless plasma deposition of glass coatings on plastic

Abstract

A chamberless, remote plasma deposition process has been used to coat silicon and plastic substrates with glass at ambient conditions. The films were deposited by introducing an organosilane precursor into the afterglow of an atmospheric plasma fed with helium and 2 vol% oxygen. The precursors examined were hexamethyldisilazane, hexamethyldisiloxane, tetramethyldisiloxane, tetramethylcyclotetrasiloxane and tetraethoxysilane. With hexamethyldisilazane, glass films were deposited at rates of up to 0.25 µm min −1 and contained as little as 13.0 mol% hydroxyl groups. These films exhibited low porosity and superior hardness and abrasion resistance. With tetramethyldisiloxane, glass films were deposited at rates up to 0.91 µm min −1. However, these coatings contained significant amounts of carbon and hydroxyl impurities (∼20 mol% OH), yielding a higher density of voids and poor abrasion resistance. In summary, the properties of glass films produced by remote atmospheric plasma deposition strongly depend on the organosilane precursor selected.

Surface characterization of the SiOx films prepared by a remote atmospheric pressure plasma jet

“…[7] In other words, the major part of film growth rate-controlling step is the adsorption of depositing plasma species in APP. Moreover, this result is consistent with several researches [8,9] that state that the substrate temperature plays a significant role in APP deposition process.…”

“…The ratio of the shoulder area of Si-O stretching mode (between 1140 and 1160 cm −1 ) to the primary peak area (between 1070 and 1080 cm −1 ) from the FTIR spectra has been correlated with the porosity degree of SiO x film [9] and the estimation result is shown in Table 1. It was found that the film with higher porosity degree and C/O ratio was obtained at lower deposition substrate temperature (e.g.…”

Atmospheric Plasma Deposition of Coatings Using a Capacitive Discharge Source

“…Comparison of this data with the infrared spectra of Figure 5 indicates that the poor abrasion resistance observed in the latter case is most likely due to higher porosity and to the incorporation of methyl groups into the glass matrix. [72] These results clearly indicate that the organosilicon precursor used in the PECVD process strongly influences the chemical and mechanical properties of the glass films.…”

“…Note that this is a remote PECVD process, where the substrate is not in contact with the plasma, so there is no ion bombardment of the surface. The films have been deposited on both silicon substrates and plastic coupons at temperatures below 100 C. [72] The precursors examined in this study were hexamethyldisilazane (HMDSN), hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), tetramethylcyclotetrasiloxane (TMCTS), and tetraethoxysilane (TEOS). Shown in Figure 4 is a plot of the deposition rate as a function of the precursor partial pressure for all these chemicals.…”

“…Above 100 mtorr, the deposition rate falls with the TMDSO partial pressure. [72] It can be seen that the deposition rate is strongly dependent on the precursor used. The following maximum rates have been reported in the literature for low pressure PECVD: 1000 nm min ±1 using HMDSO and TMCTS, [77] 10000 nm min ±1 with TEOS, [78] 400 nm min ±1 with HMDSN, [79] and 1300 nm min ±1 with TMDSO.…”