Structural and electrical characteristics of high-κ Er(2)O(3) and Er(2)TiO(5) gate dielectrics for a-IGZO thin-film transistors

In this letter, we investigated the structural and electrical characteristics of high-κ Er(2)O(3) and Er(2)TiO(5) gate dielectrics on the amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) devices. Compared with the Er(2)O(3) dielectric, the a-IGZO TFT device incorporating an Er(2)TiO(5) gate dielectric exhibited a low threshold voltage of 0.39 V, a high field-effect mobility of 8.8 cm(2)/Vs, a small subthreshold swing of 143 mV/decade, and a high I(on)/I(off) current ratio of 4.23 × 10(7), presumably because of the reduction in the oxygen vacancies and the formation of the smooth surface roughness as a result of the incorporation of Ti into the Er(2)TiO(5) film. Furthermore, the reliability of voltage stress can be improved using an Er(2)TiO(5) gate dielectric.