Electrical characteristics of GdTiO3 gate dielectric for amorphous InGaZnO thin-film transistors

• Indium–gallium–zinc oxide (a-IGZO) thin-film transistor (TFT)
• Structural and electrical properties of the GdTiO3 film were studied.
• a-IGZO TFT featuring GdTixOy dielectric exhibited better electrical characteristics.
• TFT instability investigated under positive and negative gate-bias stress conditions

In this article, we studied the structural properties and electrical characteristics of GdTiO3 gate dielectric for amorphous indium–gallium–zinc oxide (a-IGZO) thin-film transistor (TFT) applications. The a-IGZO TFT device featuring the GdTiO3 gate dielectric exhibited better electrical characteristics, including a small threshold voltage of 0.14 V, a large field-effect mobility of 32.3 cm2/V-s, a high Ion/Ioff current ratio of 4.2 × 108, and a low subthreshold swing of 213 mV/decade. Furthermore, the electrical instability of GdTiO3 a-IGZO TFTs was investigated under both positive gate-bias stress (PGBS) and negative gate-bias stress (NGBS) conditions. The electron charge trapping in the gate dielectric dominates the PGBS degradation, while the oxygen vacancies control the NGBS degradation.