Process for the manufacturing of high-density MOS-technology power devices

摘要

A process for the manufacturing of high-density MOS-technology power devices comprises the steps of: forming a conductive insulated gate layer (8) on a surface of a lightly doped semiconductor material layer (2) of a first conductivity type; forming an insulating material layer (11) over the insulated gate layer (8); selectively removing the insulating material layer (11) and the underlying insulated gate layer (8) to form a plurality of elongated windows (15) having two elongated edges (17) and two short edges (18), delimiting respective uncovered surface stripes (16) of the semiconductor material layer (2); implanting a high dose of a first dopant of the first conductivity type along two directions which lie in a plane transversal to said elongated windows (15) and orthogonal to the semiconductor material layer (2) surface, and which are substantially simmetrically tilted of a first prescribed angle (A1,A2) with respect to a direction (T) orthogonal to the semiconductor material layer (2) surface, the first angle (A1,A2) depending on the overall thickness of the insulated gate layer (8) and of the insulating material layer (11) to prevent the first dopant from being implanted in a central stripe of said uncovered surface stripes (16), to form pairs of heavily doped elongated source regions (6) of the first conductivity type which extend along said two elongated edges (17) of each elongated window (15) and which are separated by said central stripe; implanting a low dose of a second dopant of a second conductivity type along two directions which lie in said plane, and which are substantially simmetrically tilted of a second prescribed angle (A3,A4) with respect to said orthogonal direction (T), to form doped regions of the second conductivity type each comprising two lightly doped elongated channel regions (5) extending under the two elongated edges (17) of each elongated window (15); implanting a high dose of a third dopant of the second conductivity type substantially along said orthogonal direction (T), the insulating material layer (11) acting as a mask, to form heavily doped regions (4) substantially aligned with the edges (17,18) of the elongated windows (15).