[en] Thin films of poly (methyl methacrylate) (PMMA) were prepared on n-Si substrate and indium tin oxide (ITO) glass was prepared by spin coating. High frequency capacitance- voltage (C-V) and current-voltage (I-V) 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 dielectric constant value obtained was about 3.9 at 1 MHz. The breakdown field strength of PMMA can be influenced by the impurities and surface charges or the interface states in the Si substrate. The average transmittance value of the PMMA/ITO glass layer was above 80% in the visible range. (paper)