Capacitors in metal-insulator-metal structure have been fabricated with different bottom electrodes. It has been found that the observed losses are enormous at gigahertz frequencies unless due care is taken not only for the conductivity of the bottom electrode but also its thickness. Very thin bottom electrodes (thickness similar to 100 nm) modify the dielectric response substantially and major loss contributions arise from the substrate, the electrode resistance, and the contacts. A simple approach is suggested to model and experimentally evaluate the electrode resistance. (C) 1999 American Institute of Physics. [S0003-6951(99)00723-8].