Research On The Optical And Electrical Characteristics Of PMMA Film Prepared By Spin Coating Method

With the remarkable progress in the development of microelectronic technique, the traditional insulation material has not met the demand of every field of microelectronic devices. Especially, the organic thin-film transistor (OTFT) shows great application potential in electronic products owing to its low-cost and good performance in the recent years. While the semiconductor materials play an important role in OTFTs, the insulation materials also can change the electrical property of OTFT significantly. Compared with inorganic insulation materials, organic insulating materials are low-cost and more suitable for the flexible substrate which can be used to a new generation of flat-panel display. Poly (methyl methacrylate) (PMMA) has been a promising transparent organic dielectric material for OTFTs.This article is based on the basic characters of Metal-Oxide-Semiconductor (MOS) structure to study the electrical characteristic of PMMA film. The thin films of PMMA were prepared on n-Si substrate and ITO Glass by spin coating, respectively. XRD spectrum indicates the amorphous nature of PMMA film. Annealing can influence the surface morphology of PMMA film. Capacitance-voltage (C-V) and current-voltage (â… -â…¤) characterization were carried out on the Al/PMMA/n-Si and Al/PMMA/ITO glass structures, with the films as the insulator layer to evaluate the electrical properties. For the PMMA the relative permittivity obtained was about 3.99 at 1MHz which is similar to the SiO2. From C-V characterization in the frequency range of 5 KHz-2MHz, the relative permittivity decreased with the increasing frequency. The breakdown field strength of PMMA film was 3.2MV/cm for MIS and 5.8 MV/cm for MIM structure, the difference may due to the different substrate. The average transmittance value of the PMMA/ITO glass structure was above 80% by UV-VIS. The PMMA film played a role in anti-reflection from 350nm to500nm.