Characteristics of short-channel amorphous In-Ga-Zn-O thin film transistors and their circuit performance as a load inverter

Abstract

The characteristics of amorphous In-Ga-Zn-O(IGZO) thin film transistors (TFTs) and load inverters with a short channel length were studied. The IGZO TFTs showed a mobility value of > 5 cm(2)/Vs with a V-th value of -1.62 V. No degradation of the TFT properties, such as a negative shift of V-th or degradation of the subthreshold slope by the short-channel effect, were observed down to a channel length of 2 mu m. A load inverter using an IGZO TFT with a gate length of 2 mu m and resistor of 1 M Omega was fabricated and characterized, and a voltage gain of 4 was obtained at a V-DD value of 10 V. Additionally, the action of a dynamic inverter operating at frequencies of 1 and 10 kHz was characterized. Complete inverter action was obtained at 1 kHz, while an delay time of 0.53 mu s was observed at 10 kHz. These promising results indicate that short channel IGZO TFTs are candidate for TFTs in the display industry, including active-matrix organic light-emitting diodes or multi-view three-dimension TV.