Lateral MOS power transistor

1. Field of the Invention A MOS power transistor formed in an epitaxial layer of a first conductivity type, the MOS power transistor being formed on the front surface of a heavily-doped substrate of the first conductivity type, including a plurality of alternate drain and source fingers of the second conductivity type separated by a channel, conductive fingers covering each of the source fingers and of the drain fingers, a second metal level connecting all the drain metal fingers and substantially covering the entire source-drain structure. Each source finger includes a heavily-doped area of the first conductivity type in contact with the epitaxial layer and with the corresponding source finger, and the rear surface of the substrate is coated with a source metallization.