Mechanical flexibility is attractive for many electronic applications, including flat-panel displays, electronic paper, medical X-ray sensor arrays, and photovoltaic modules. Making electronics flexible adds a new dimension to the design and utilization of electronic materials. Among the most important materials that need be made flexible is an optically clear insulator that can function as a gate dielectric and as an environmental permeation barrier. We introduced a new SiO2-silicone hybrid material that meets these functions. The hybrid consists of ~ 90% SiO2 and ~ 10% silicone polymer , which we deposit by plasma-enhanced chemical vapor deposition from a silicone monomer and excess oxygen on substrates at room temperature. Its electrical properties were evaluated on metal/~100 nm hybrid/p-type Si capacitors from measurements with an HP 4275A LCR meter and an HP 4155A parameter analyzer. The hybrid has a relative dielectric constant of 4.0, a leakage current of 0.08 A/cm2 at an electrical field of 1 MV/cm, and a breakdown field of 8 MV/cm. To test its mechanical flexibility in a device, the hybrid was used the a gate dielectric in hydrogenated amorphous-silicon thin film transistors (a-Si:H TFTs). The TFTs can be bent to a tensile strain of up to 10 times of that of conventional a-Si:H / SiNx TFTs . To test its permeability for atmospheric gases, we conducted accelerated tests at elevated temperature and humidity of hybrid encapsulated organic light-emitting diodes (OLEDs). At 65C and 85% relative humidity, the water vapor transmission rate is at most 10^-6 g/m^2/day . Because the hybrid is deposited at room temperature from inexpensive sources, is mechanically flexible and electrically and chemically impermeable, it is a suitable material for flexible electronics.
We report the dielectric properties of the hybrid, the electrical and mechanical performance of a-Si:H TFTs with the hybrid gate dielectric, and the permeability of the hybrid used as encapsulation for OLEDs.