Aqueous Solution Induced High-Dielectric-Constant AlOx :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 AlOx : Y dielectrics with a small amount of yttrium homogeneously distributed in AlOx matrix through an alternate spin-coating process. The AlOx : Y films demonstrate superior characteristics, such as improved surface morphology, better capacitance coupling effect, smaller dielectric dispersion, and similar leakage current density compared to AlOx films of nearly twofold thickness. By elevating the pre-baking temperature, the dielectric performance of AlOx : Y films has been further optimized, exhibiting a near-atomically smooth surface, a low current density of 8 x 2x10(-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 cm(2) 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.