Effects of Oxygen Injection Rates on a-IGZO Thin-film Transistors with Oxygen Plasma Treatment

Abstract

In this study, investigate the influence of oxygen plasma treatment on the oxide channel layer of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors based on the amount of oxygen gas injected. The a-IGZO channel layer thin-film transistors (TFTs) were fabricated with plasma treatment of zero, three, six, or nine standard cubic centimeters per minute (sccm) of oxygen gas injection into the a-IGZO channel layer using gun-type plasma cells from a molecular beam epitaxy system after the post-annealing process. In this experiment, oxygen plasma treatment on the a-IGZO channel layer improved the electrical and surface-area performance. Of all the treatment conditions, the a-IGZO channel layer TFT treated with plasma from an injection of 6 sccm of oxygen gas showed excellent transfer characteristics. They include saturation mobility of 14.4 cm²/Vs, a threshold voltage of 4.5 V, an on/off current ratio of 1.1 × 10<SUP>8</SUP>, and an inverse subthreshold slope of 0.7 V/dec. Surface morphology analyses confirmed that increases in the oxygen gas injection rate decreased. A dynamic inverter test was conducted by configuring the logic circuit for the a-IGZO channel layer TFT, which verified the possibility for future application of the backplane device in active-driven displays.