An array substrate for a liquid crystal display device includes a substrate having a display area and a driving circuit area, a first semiconductor layer formed on the substrate in the display area, the first semiconductor layer having an active region and source and drain regions at opposing sides of the active region, a gate insulating layer formed on the first semiconductor layer, a gate electrode formed on the gate insulating layer and over the active region, the gate electrode being wider than the gate insulating layer, and an interlayer insulating layer formed over the substrate including the gate electrode, wherein the interlayer insulating layer, the gate electrode, the gate insulating layer, and the active region define a first cavity.