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In this work SiN x thin films have been deposited by Hot-Wire Chemical Vapor Deposition (HW-CVD) technique to be used as encapsulation barriers for flexible organic electronic devices fabricated on polyethylene terephthalate (PET) substrates. First results of SiN x multilayers stacked and stacks of SiN x single-layers (50 nm each) separated by an Ar-plasma surface treatment are reported. The encapsulation barrier properties of these different multilayers are assessed using the electrical calcium degradation test by monitoring changes in the electrical conductance of encapsulated Ca sensors with time. The water vapor transmission rate is found to be slightly minimized (7 × 10 − 3 g/m 2 day) for stacked SiN x single-layers exposed to argon plasma treatment during a short time (2 min) as compared to that for stacked SiN x single-layers without Ar plasma treatment. [ABSTRACT FROM AUTHOR]

Abstract: In this work we produce and study silicon nitride (SiNx) thin films deposited by Hot Wire Chemical Vapor Deposition (HW-CVD) to be used as encapsulation barriers for flexible organic photovoltaic cells fabricated on polyethylene terephthalate (PET) substrates in order to increase their shelf lifetime. We report on the results of SiNx double-layers and on the equivalent double-layer stack where an Ar-plasma surface treatment was performed on the first SiNx layer. The Ar-plasma treatment may under certain conditions influences the structure of the interface between the two subsequent layers and thus the barrier properties of the whole system. We focus our attention on the effect of plasma treatment time on the final barrier properties. We assess the encapsulation barrier properties of these layers, using the calcium degradation test where changes in the electrical conductance of encapsulated Ca sensors are monitored with time. The water vapor transmission rate (WVTR) is found to be ~3×10−3 g/m2·day for stacked SiNx double-layer with 8min Ar plasma surface treatment. [Copyright &y& Elsevier]

Permeation barriers for organic electronic devices on polymer flexible substrates were realized by combining stacked silicon nitride (SiN x ) single layers (50 nm thick) deposited by hot-wire chemical vapor deposition process at low-temperature (~ 100°°C) with a specific argon plasma treatment between two successive layers. Several plasma parameters (RF power density, pressure, treatment duration) as well as the number of single layers have been explored in order to improve the quality of permeation barriers deposited on polyethylene terephthalate. In this work, maximum ion energy was highlighted as the crucial parameter making it possible to minimize water vapor transmission rate (WVTR), as determined by the electrical calcium test method, all the other parameters being kept fixed. Thus fixing the plasma treatment duration at 8 min for a stack of two SiN x single layers, a minimum WVTR of 5 × 10 − 4 g/(m 2 day), measured at room temperature, was found for a maximum ion energy of ~ 30 eV. This minimum WVTR value was reduced to 7 × 10 − 5 g/(m 2 day) for a stack of five SiN x single layers. The reduction in the permeability is interpreted as due to the rearrangement of atoms at the interfaces when average transferred ion energy to target atoms exceeds threshold displacement energy. [ABSTRACT FROM AUTHOR]