Low-temperature-fabricated InGaZnO4 thin film transistors on polyimide clean-room tape

Amorphous (alpha-)InGaZnO4 thin film transistors (TFTs) were fabricated on polyimide clean-room tape at low temperature (< 100 degrees C). The alpha-InGaZnO4 films with an n-type carrier concentration of similar to 10(16) cm(-3) were deposited by rf-magnetron sputtering in a mixed ambient of Ar/O-2. The bottom-gate-type TFTs showed good saturation mobility (similar to 5.3 cm(2) V-1 s(-1)), drain current on-to-off ratio of approximately 10(5), threshold voltage of 1.1 V, and subthreshold gate-voltage swing of 0.55 V decade(-1). These results were comparable to those of the same oxide TFTs that we have fabricated on either glass or polyethylene terephthalate substrates. The results demonstrate that even polyimide clean-room tape can be an appropriate substrate for inexpensive-flexible-adhesive-transparent electronic devices.