Preparation of Poly (methyl methacrylate) thin film Capacitors on ITO-glass substrate

Abstract

In electronic devices, some important materials having a high dielectric constant can be used. Polymer-ceramic composites have a high dielectric constant and are widely used for embedded capacitor applications. It is critical to use polymer poly methyl methacrylate (PMMA) as thin films capacitors for the gate dielectric in organic field-effect transistors (OFETs). In this work, thin films of polymer PMMA were prepared by using spin coating at different speeds (1500, 2000, 2500, 3000 and 3500 rpm) to control the film thickness and study the effect of the thickness on the dielectric properties. Thin film thickness was measured by using field emission scanning electron microscopy (FESEM) to take cross-section images. We found that the film thickness decreased with increased rotational speed from 27387 nm at 1500 rpm to 10600 nm at 3500 rpm. The values of the capacities were nearly stable with increasing frequencies when thickness equal to or larger than (14366 nm), but their increased with increased frequency at thickness (10600 nm), and the dielectric constant also decreases with increasing thin films thickness. The best result of capacitance value was at thickness 10600nm which equal to (5.753 nF) and dielectric constant equal to (3.511) which represents best value that can be used as dielectric gate for Organic Field Effect Transistor (OFET).