A semiconductor structure including a substrate, a first well, a field oxide layer, a first conductive line and a second conductive line is provided. The substrate has a first conductivity type. The first well is formed on the substrate and has a second conductivity type. The field oxide layer is disposed on the first well. The first conductive line is formed on the field oxide layer and is in direct contact with the field oxide layer. The second conductive line is formed on the field oxide layer and is in direct contact with the field oxide layer. The first conductive line is spaced apart from the second conductive line.