Patent ID: 7525153

Claim:
A laterally double-diffused metal oxide semiconductor transistor (LDMOS) device, comprising: a substrate comprising a first conductive dopant; a first well comprising a second conductive dopant and formed in a part of the substrate; a drain located in the first well; a second well comprising the first conductive dopant and formed in another part of the substrate, wherein the depth of the second well is substantially equal to that of the first well; and a source located in the second well, the source comprising a lightly doped region and a heavily doped region extending downwardly from a top surface of the substrate, wherein the lightly doped region is deeper than the heavily doped region; a plurality of field oxide films (FOXs) all formed on the substrate, a first field oxide film and a second field oxide film located in the first well, a third field oxide film located in the second well, wherein the third field oxide film contacts with the lightly doped region and is separated from the heavily doped region by a distance.