Logic circuit and semiconductor device

A display device comprising:

• a transistor over a substrate;
• a light-emitting element electrically connected to the transistor;
• and
• a color filter layer,
• wherein the color filter layer is located over the transistor and under the light-emitting element,
• wherein a channel formation region of the transistor comprises an oxide semiconductor,
• wherein a hydrogen concentration of the oxide semiconductor is smaller than or equal to 5×1019/cm3, and
• wherein an off-state current of the transistor is smaller than or equal to 1×10−16 A/μm at a measurement temperature of 120° C. and a drain voltage of 6 V.

A display device comprising:

• a transistor over a substrate;
• a light-emitting element electrically connected to the transistor;
• and
• a color filter layer,
• wherein the color filter layer is located over the transistor and under the light-emitting element,
• wherein a channel formation region of the transistor comprises an oxide semiconductor, and
• wherein an off-state current of the transistor is smaller than or equal to 1×10−13 A when a voltage between source and drain of the transistor is 10 V.