An unexpected rapid anneal of electrically active defects in an ultra-thin (15.5 nm) polar polyimide film at and below glass transition temperature (Tg) is reported. The polar polymer is the gate dielectric of a thin-film-transistor (TFT). Gate leakage current density (Jg) through the polymer initially increases with temperature, as expected, but decreases rapidly at Tg 60 °C. After approximately two minutes at Tg, the leakage is reduced by nearly three orders of magnitude. A concomitant observation is that drain current (Id) gate voltage (Vg) hysteresis decreases with temperature, reaching zero at nearly the same temperature where Jg collapses. As Jg drops further, the drain current hysteresis increases again but in the opposite direction. This combination strongly supports the interpretation of rapid defect annealing.
Citation: Advanced Functional Materials
Pub Type: Journals
defects annealing, polar polymer, glass transition temperature, CP1