Aqueous Solution Induced High-Dielectric-Constant AlO x :Y Films for Thin-Film Transistor Applications

Aqueous solution induced method is regarded as a promising route to realize high-performance metal oxide thin film transistors at low temperature with an economical and environment friendly process. In this paper, we report the synthesis of multi-component AlO x :Y dielectrics with a small amount of yttrium homogeneously distributed in AlO x matrix through an alternate spin-coating process. The AlO x :Y films demonstrate superior characteristics, such as improved surface morphology, better capacitance coupling effect, smaller dielectric dispersion, and similar leakage current density compared to AlO x films of nearly twofold thickness. By elevating the pre-baking temperature, the dielectric performance of AlO x :Y films has been further optimized, exhibiting a near-atomically smooth surface, a low current density of 8.2×10−8 A cm−2 at 2 MV/cm, and a dielectric constant of 7.4. And the corresponding thin-film transistor with amorphous InGaZnO channel shows a narrow working voltage range (<2.5 V), a field-effect mobility around 10 cm2 V−1 s−1, and an on/off current ratio exceeding 107 coupled with the gate current lower than 1 nA in the entire operation range.