Films of a hybrid material with part-SiO2 part-silicone character are deposited as environmental barriers on bottom-emitting and on transparent organic light-emitting diodes. Devices coated with this barrier have lifetimes of up to ∼7500h when stored at 65°C and 85% relative humidity, by far exceeding the industrial requirement of 1000h. The intensity of the Si–O–Si absorption at the wavenumber of 1075cm−1, the wetting angle by water, and the indentation hardness support the interpretation of a homogeneous material with the properties of a SiO2-silicone hybrid. The films remain intact over 58600cycles of bending to ∼0.2% tensile strain.

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The conventional, brittle, silicon nitride barrier layer and gate insulator in amorphous silicon thin-film transistors (a-Si:H TFTs) on 50 μm thick polyimide foil was replaced by a resilient, homogeneous, hybrid of silicon dioxide and silicone polymer. The transistor structures can be bent down to 0.5 mm radius (5% strain) in tension and down to 1 mm radius (2.5% strain) in compression. This pronounced flexibility shifts the criterion for reversible bending away from a-Si:H TFT backplanes and toward the materials for substrate and encapsulation. It qualifies a-Si:H TFTs for pull-out display screens in handheld devices.

We characterize a recently discovered material that forms an ultra-hermetic environmental barrier layer for the protection of organic light-emitting displays. The layer is deposited by plasma-enhanced chemical vapor deposition (PE-CVD) from the nontoxic precursor gases, hexamethyl disiloxane and oxygen. We measured the PE-CVD deposition rate, wet and dry etch rates, IR absorption spectrum, wetting contact angle with water, surface roughness and phase shift from atomic force microscopy, coefficient of thermal expansion, elastic modulus, critical tensile strain, indentation hardness, optical absorption spectrum, refractive index, relative dielectric constant, and electrical conduction, many over a range of PE-CVD conditions. The properties reflect a continuous transition from those of plasma-polymerized silicon to those of silicon dioxide prepared by thermal oxidation of silicon. In addition to low permeability, the critical strain, fracture toughness, thermal expansion coefficient, optical transmittance, and refractive index have values that are desirable in a hermetic encapsulant for organic light-emitting displays.

A new gate dielectric material is used to fabricate hydrogenated amorphous-silicon (a-Si:H) thin-film transistors (TFTs) with high field-effect mobilities. The dielectric is a homogeneous SiO2-silicone hybrid, which is deposited by plasma-enhanced chemical vapor deposition system at nominal room temperature. This new dielectric results in a-Si:H TFTs with measured field-effect mobilities of ∼2 cm2/V s for electrons and ∼0.1 cm2/V s for holes.