The present disclosure relates to a semiconductor integrated circuit device. The semiconductor integrated circuit device may include a plurality of stacked structures and a vertical channel transistor. The plurality of stacked structures is stacked in a vertical direction. The vertical channel transistor is formed through the plurality of stacked structures. The vertical channel transistor comprises a gate formed with a conformal thickness on a sidewall of a contact hole penetrating the plurality of stacked structures, a gate insulating layer formed along a surface of the gate within the contact hole. The channel layer extends in parallel with the vertical direction.