Abstract: A high voltage device includes a substrate, a first LDMOS transistor and a second LDMOS transistor disposed on the substrate. The first LDMOS transistor includes a first gate electrode disposed on the substrate. A first STI is embedded in the substrate and disposed at an edge of the first gate electrode and two first doping regions respectively disposed at one side of the first STI and one side of the first gate electrode. The second LDMOS transistor includes a second gate electrode disposed on the substrate. A second STI is embedded in the substrate and disposed at an edge of the second gate electrode. Two second doping regions are respectively disposed at one side of the second STI and one side of the second gate electrode, wherein the second STI is deeper than the first STI.

Abstract: A high voltage device includes a substrate, a first LDMOS transistor and a second LDMOS transistor disposed on the substrate. The first LDMOS transistor includes a first gate electrode disposed on the substrate. A first STI is embedded in the substrate and disposed at an edge of the first gate electrode and two first doping regions respectively disposed at one side of the first STI and one side of the first gate electrode. The second LDMOS transistor includes a second gate electrode disposed on the substrate. A second STI is embedded in the substrate and disposed at an edge of the second gate electrode. Two second doping regions are respectively disposed at one side of the second STI and one side of the second gate electrode, wherein the second STI is deeper than the first STI.

Abstract: A high voltage device includes a substrate, a first LDMOS transistor and a second LDMOS transistor disposed on the substrate. The first LDMOS transistor includes a first gate electrode disposed on the substrate. A first STI is embedded in the substrate and disposed at an edge of the first gate electrode and two first doping regions respectively disposed at one side of the first STI and one side of the first gate electrode. The second LDMOS transistor includes a second gate electrode disposed on the substrate. A second STI is embedded in the substrate and disposed at an edge of the second gate electrode. Two second doping regions are respectively disposed at one side of the second STI and one side of the second gate electrode, wherein the second STI is deeper than the first STI.

Abstract: A semiconductor structure is provided. The semiconductor structure comprises a substrate, a deep well formed in the substrate, a first well and a second well formed in the deep well, a gate electrode formed on the substrate and disposed between the first well and the second well, a first isolation, and a second isolation. The second well is spaced apart from the first well. The first isolation extends down from the surface of the substrate and is disposed between the gate electrode and the second well. The second isolation extends down from the surface of the substrate and is adjacent to the first well. A ratio of a depth of the first isolation to a depth of the second isolation is smaller than 1.

Abstract: A semiconductor structure is provided. The semiconductor structure comprises a substrate, a deep well formed in the substrate, a first well and a second well formed in the deep well, a gate electrode formed on the substrate and disposed between the first well and the second well, a first isolation, and a second isolation. The second well is spaced apart from the first well. The first isolation extends down from the surface of the substrate and is disposed between the gate electrode and the second well. The second isolation extends down from the surface of the substrate and is adjacent to the first well. A ratio of a depth of the first isolation to a depth of the second isolation is smaller than 1.