PMMA-SiO2 organic–inorganic hybrid films: determination of dielectric characteristics

• Published in: Journal of sol-gel science and technology 2011-04, Vol.58 (1), p.218-224
• Main Authors: Morales-Acosta, M. D., Quevedo-López, M. A., Gnade, Bruce E., Ramírez-Bon, R.
• Format: Article
• Language: English
• Subjects: Absorption spectra; Ceramics; Chemistry; Chemistry and Materials Science; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Composites; Coupling agents; Density; Dielectric properties; Electrical properties; Electronic devices; Exact sciences and technology; Fourier transforms; Frequency ranges; General and physical chemistry; Glass; Heat treatment; Inorganic Chemistry; Materials Science; MIS (semiconductors); Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper; Permittivity; Polymethyl methacrylate; Silicon dioxide; Silicon substrates; Sol-gel processes; Spin coating; Tetraethyl orthosilicate; Thin films
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-010-2380-9

Organic–inorganic hybrid thin films have been prepared by a modified sol–gel route using tetraethyl orthosilicate as the inorganic (silica) source, methyl methacrylate (MMA) as the organic source, and 3-trimetoxysilylpropyl methacrylate as the coupling agent. The films were prepared by spin coating on Si (100) p-type substrates and subsequently heat-treated at 90 °C. Fourier transform infrared results reveal a set of absorption bands associated with the formation of both PMMA and SiO 2 phases in the hybrid films. Capacitance–voltage ( C – V ) characterization was carried out on metal-insulator-metal (MIM) and metal-insulator-semiconductor (MIS) structures, with the hybrid films as the insulator layer to evaluate the electrical properties. We present a detailed comparative analysis of the dielectric constant obtained from C – V characterization in the frequency range of 1 kHz–1 MHz. For the PMMA-SiO 2 hybrid material the dielectric constant values obtained were around 9.5 at 1 MHz which is superior to the values reported for thermally grown SiO 2 and pure PMMA materials. The interface state density for PMMA-SiO 2 on Si was approximately 10 10  cm −2 , which is comparable to the standard SiO 2 /Si structures. Due to the electrical behavior and low processing temperatures this hybrid dielectric is a very promising candidate for flexible electronic devices and its subsequent implementation does not require complex equipment.