Dielectric breakdown in plasma-polymerized aniline film

Summary form only given, as follows. Plasma-polymerized films have been considered for use in applications such as photoemission, electron field emission displays, low dielectric constant material used for microelectronic interlayer dielectrics, and as protective coatings for superconductors. Molecules used as the monomer feed material have become high in molecular weight and complex in structure including aromatic hydrocarbons and dyes. In many applications, these films are exposed to large electric fields, thus their dielectric breakdown characteristics must be understood. In our work, the impact of plasma reactor conditions on film dielectric breakdown is studied. A pressure contact technique is utilized to induce dielectric breakdown of plasma polymerized aniline (PPAni) films. Pressure contacts have important advantages over conventionally processed electrodes: 1) they can be quickly moved from site to site on the film being evaluated, 2) they eliminate fabrication steps that could modify the film being studied, 3) the pressure contact can be easily removed and the test site inspected with surface diagnostic tools, and 4) electric field enhancement near electrode edges can be controlled by altering the electrode shape in 3 dimensions. The test structure consists of an indium tin oxide (ITO) substrate on glass with 100-500 nm PPAni film deposited onto the ITO. The ITO becomes the anode (positive electrode) while a metal sphere pressed onto the PPAni becomes the cathode (negative electrode). Voltage pulses with adjustable amplitude (0-200 V) and adjustable duration (0.01 ms to 1s) are applied. Transducers measure voltage, current and emitted light. Current pulses (on the order of 50 mA) and light emission accompany dielectric breakdown. The following features will be studied as they influence dielectric breakdown: film morphology (surface roughness, nodules, pinholes, etc.), cathode sphere diameter, cathode sphere material and compressive force applied to the cathode sphere.