Provided is a tap cell including a substrate, a first well, a second well, a first doped region, and the second doped region. The substrate has a first region and a second region. The first well has a first dopant type and includes a first portion disposed in the first region and a second portion extending into the second region. The second well has a second dopant type and includes a third portion disposed in the second region and a fourth portion extending into the first region. The first doped region having the first dopant type is disposed in the second portion of the first well and the third portion of the second well along the second region. The second doped region having the second dopant type is disposed in the first portion of the first well and the fourth portion of the second well along the first region.