Abstract: A double-RESURF LDMOS fabrication method utilizes a shared mask to form separately patterned N+ buried layer (NBL) and P+ buried layer (PBL) regions. The mask includes two opening types (e.g., large and small), and the P-type and N-type implant materials are separately directed onto the mask at different implant angles, such that the N-type implant passes through both opening types to form a first pattered implant region in both a first region and a surrounding second region, and such that the P-type implant material passes only through the larger openings and forms a second pattered implant region only in the first substrate portion. An optional epitaxial layer is deposited over the substrate and annealed to form the separately patterned PBL and NBL in the epitaxial layer, where a portion of the PBL diffuses above the NBL and forms a P-surf region below the LDMOS's N-drift region.