Abstract
We measured a significantly low off-state current (135 yA/µm at 85 °C) of a metal oxide semiconductor (MOS) transistor using indium–gallium–zinc oxide (IGZO), which is an oxide semiconductor material. Note that "y" is 10-24. A transistor in which the hydrogen concentration in an IGZO film is lowered (5×1019 cm-3 or lower) was used. To estimate the minute current accurately, we established a measurement method in which changes in the amount of electrical charge are measured for a long time. Such extremely low off-state current characteristics show promise for new applications of IGZO transistors in memories.