18973522. LOGIC CIRCUIT AND SEMICONDUCTOR DEVICE (SEMICONDUCTOR ENERGY LABORATORY CO., LTD.)
LOGIC CIRCUIT AND SEMICONDUCTOR DEVICE
Organization Name
SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
Inventor(s)
Shunpei Yamazaki of Setagaya JP
LOGIC CIRCUIT AND SEMICONDUCTOR DEVICE
This abstract first appeared for US patent application 18973522 titled 'LOGIC CIRCUIT AND SEMICONDUCTOR DEVICE
Original Abstract Submitted
A logic circuit includes a thin film transistor having a channel formation region formed using an oxide semiconductor, and a capacitor having terminals one of which is brought into a floating state by turning off the thin film transistor. The oxide semiconductor has a hydrogen concentration of 5×10(atoms/cm) or less and thus substantially serves as an insulator in a state where an electric field is not generated. Therefore, off-state current of a thin film transistor can be reduced, leading to suppressing the leakage of electric charge stored in a capacitor, through the thin film transistor. Accordingly, a malfunction of the logic circuit can be prevented. Further, the excessive amount of current which flows in the logic circuit can be reduced through the reduction of off-state current of the thin film transistor, resulting in low power consumption of the logic circuit.