Novel digital memory devices were fabricated with a thermally and dimensionally stable polyimide containing carbazole moieties in its side groups by using a simple and conventional solution coating process. The devices exhibit excellent unipolar ON and OFF switching behavior. With very low power consumption, the devices can be repeatedly written, read, and erased in air. The ON/OFF current ratio of the devices is high up to 1011. The high ON/OFF switching ratio and stability of the devices, as well as their repeatable writing, reading, and erasing capability with low power consumption, open up the possibility of the mass production of high performance non‐volatile memory devices at low cost.

Electrically programmable fuse‐type polymer memory devices based on hyperbranched copper phthalocyanine polymer thin films are fabricated. The devices have novel write‐once‐read‐many (WORM) memory characteristics, with a high ON/OFF current ratio (of 106) and a high electrical stability, thus opening up the possibility of a low‐cost mass production of high‐performance, nonvolatile polymer memory devices.

Thin films (20-150 nm thickness) of poly(o-anthranilic acid) with various doping levels were prepared on silicon substrates with deposited indium tin oxide, and their topography and current-voltage (I-V) characteristics were quantitatively investigated using current-sensing atomic force microscopy with a platinum-coated tip. The films were found to have a surface morphology like that of orange peel, with a periodic modulation and a surface roughness. The films exhibited nonuniform current flows and I-V characteristics that depended on the doping level as well as on the film thickness. Films with a high doping level were found to exhibit Zener diode switching behavior, whereas the films with a very low doping level (or that were dedoped) exhibited no current flow at all, and so are insulators. Interestingly, self-doped films (which are at an intermediate doping level) were found to have a novel electrical bistability, i.e., a switching characteristic like that of Schottky diodes, and increasingly insulating characteristics as the film thickness was increased. The films with thickness < or =62 nm, which exhibited this novel and stable electrical bistability, can potentially be used in the fabrication of high-density, stable, high-performance digital nonvolatile memory devices based only on transistors. The measured current images and I-V characteristics indicate that the electrical switching and bistability of the films are governed by local filament formation and charge traps.

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