Patent ID: 7560368
Filing Date: 2009-07-14
Classification: H01L

Abstract:
1. A process for fabricating an insulated gate integrated power device comprising the operations of: a) constituting a drain semiconducting substrate doped with a dopant of a first type of conductivity and forming an edge structure of the insulated gate integrated power device, b) forming an insulated gate electrode by growing or depositing a dielectric film of gate oxide on the surface of said drain semiconducting substrate and depositing thereon a conductive layer of polysilicon, c) covering said conductive polysilicon layer with an insulating layer or multilayer of dielectric material deposited thereon, d) depositing a layer of photo resist on said deposited insulating layer, e) defining said gate electrode by masking and anisotropic selective etching of said deposited insulating layer and of said polysilicon layer forming apertures through the area of which the integrated structure and the relative source contact of each elementary cell constituting said power device will be formed, and wherein the successive sequence comprises the operations of: f) performing a first ion implantation of a dopant appropriate to constitute a body region of opposite type of conductivity of said drain semiconducting substrate with certain tilt and twist angles such to determine a shade zone inside said aperture in function of the total height of the definition edge of the stack composed of said polysilicon layer, said insulating layer and said layer of photo resist, and of the width of the aperture, with an implant dose and energy appropriate to obtain a certain concentration and channel length; g) performing at least a second ion implantation at the same conditions of said first implantation but with different tilt and twist angles to define a central window in the shade pattern on the implanted cell area; h) removing of said layer of photo resist; i) activating the implanted dopants by heat treatment; j) performing a source ion implantation on the whole area of said aperture of a dopant of the same type of conductivity of the drain substrate and opposite to that of the dopant of said body implantations with dose and energy of implant appropriate to constitute a source region surrounded by said body region; k) activating of the implanted source dopant by heat treatment; l) depositing a sacrificial layer of a dielectric material under conditions of substantial uniformity of thickness of deposition over the steps of the definition borders of said apertures; m) anisotropic etching of the sacrificial layer for leaving a dielectric spacer on the definition edge surfaces of said apertures; n) after the operations of activating of the implanted source dopant and covering, anisotropic etching of the semiconducting substrate for a depth deeper than the depth of said source region but shallower than the depth of said body region, exposing within the area of each cell surfaces of said source region, of said body region and, at the bottom of the trench, a zone of said drain substrate surrounded laterally by said body region; o) opening of contacts on said gate electrode through a dedicated photo resist mask; p) removing the photo resist mask and depositing one or more conductive metal layers for establishing inside said trench an electric contact with both the source region and the body region and determining a good barrier height of the Schottky contact established with the drain substrate on at least a portion of the bottom surface of said trench.