Flexible BSA MIM capacitor with negative voltage coefficient for RF applications

Abstract

In this report, Bovine Serum Albumin-based Metal-Insulator-Metal structures on Indium doped Tin Oxide coated flexible Polyethylene Terephthalate substrates with Aluminum (Al) as the top electrode have been fabricated and studied in detail. The thickness of the film was measured using a Field Emission Scanning Electron Microscope. The Fourier Transform Infrared Attenuated Total Reflectance spectrum confirms the presence of both amide-I and amide-II in the protein film. Ultraviolet-Visible Spectroscopy was performed for the absorption spectrum used to extract the optical bandgap. The surface roughness of the film was estimated by Atomic Force Microscopy. Electrical characterization of the devices gives a high capacitance density with a negative quadratic coefficient and a low dissipation factor, showing their potential for Radio Frequency/analog application. The number of dipoles (N-PD) is found to be 1.01x10(18)cm(-3) with a permanent dipole moment (mu (0)) of 2.92x10(-25) C m at an applied frequency of 1MHz. The devices show high reliability resistant to degradation, studied by Constant Voltage Stressing. We also examined the performance of these flexible devices by repeated bending with different bending radii.