Abstract
This thesis examines the origin and the importance of phase in transmission electron microscopy. Because the low contrast of weak phase object, we develop the electrostatic phase plate to improve the phase contrast. The phase plate consists of three electrode layers and two dielectric layers, which forms a uniform electrostatic field and shifts the phase of electron beam. The structure of the phase plate is the same as an Einzel lens. All the parameters of phase plate, such as electrostatic field distribution, electrons trajectory, phase change from phase plate, and the frequencies blocked by the ring, were calculated. The simulation of electrostatic field distribution is also compared to the results measured by Atomic Force Microscopy (AFM). With these parameters, the profile of the phase plate can be determined, and the factors for fabrication are easily controlled. At last, the images taken after using a phase plate are shown and key points and suggestions are given.