Effects of Ar/N₂ flow ratio on sputtered-AlN film and its application to low-voltage organic thin-film transistors

In this work, we applied a low-temperature (150°C) alumina nitride (AlN) film as the gate dielectric in organic thin-film transistors (OTFTs). It was found that the Poole-Frenkel-type leakage can be suppressed by increasing the nitrogen gas ratio in the deposition process. The thin and low-leakage AlN dielectric was characterized and then utilized in pentacene-based OTFTs. The proposed AlN dielectric greatly lowers the OTFT operating voltage (<5 V). A low threshold voltage (-1.5 V), a low subthreshold swing (104 mV/decade), and a high on/off current ratio (>10⁵) were also obtained for the AlN-OTFTs.