A schottky diode includes a schottky junction, an ohmic junction, a first isolation structure and a plurality of doped regions. The schottky junction includes a first well in a substrate and a first electrode contacting the first well. The ohmic junction includes a junction region in the first well and a second electrode contacting the junction region. The first isolation structure is disposed in the substrate and separates the schottky junction from the ohmic junction. The doped regions are located in the first well and under the schottky junction, wherein the doped regions separating from each other constitute a top-view profile of concentric circles.