Method for forming a drift region of a superjunction device

A method, comprising:

• forming at least one drift region section that includes a semiconductor layer with first regions of a first doping type and second regions of a second doping type, wherein the first regions and the second regions are arranged alternatingly in a first lateral direction of the semiconductor layer,
• wherein forming the at least one drift region section comprises:
• forming an implantation mask on top of a first surface of the semiconductor layer, wherein the implantation mask comprises first openings each having a first width in the first lateral direction;
• in a first implantation process, implanting dopant atoms of the first doping type through the first openings into the first surface to form first implanted regions in the semiconductor layer;
• increasing a size of the first openings to obtain second openings having a second width in the lateral direction;
• in a second implantation process, implanting dopant atoms of the second doping type through the second openings into the first surface to form second implanted regions and third implanted regions in the semiconductor layer, wherein the second implanted regions result from implanting dopant atoms of the second doping type into the first implanted regions, and wherein the third implanted regions result from implanting dopant atoms of the second doping type into regions of the semiconductor layer that are uncovered in the process of increasing the size of the first openings in the implantation mask;
• removing the implantation mask;
• and
• after removing the implantation mask, in a third implantation process, implanting dopant atoms of the first doping type into the first surface to form fourth implanted regions, fifth implanted regions, and sixth implanted regions in the semiconductor layer, wherein the fourth implanted regions result from implanting dopant atoms of the first doping type into the second implanted regions, wherein the fifth implanted regions result from implanting dopant atoms of the first doping type into the third implanted regions, and wherein the sixth implanted regions result from implanting dopant atoms of the first doping type into regions of the semiconductor layer that are uncovered by removing the implantation mask.

A method, comprising:

• forming at least one drift region section that includes a semiconductor layer with first regions of a first doping type and second regions of a second doping type, wherein the first regions and the second regions are arranged alternatingly in a first lateral direction of the semiconductor layer,
• wherein forming the at least one drift region section comprises:
• forming an implantation mask on top of a first surface of the semiconductor layer, wherein the implantation mask comprises first openings each having a first width in the first lateral direction;
• in a first implantation process, implanting dopant atoms of the first doping type through the first openings into the first surface;
• increasing a size of the first openings to obtain second openings having a second width in the lateral direction;
• in a second implantation process, implanting dopant atoms of the second doping type through the second openings into the first surface;
• removing the implantation mask;
• and
• after removing the implantation mask, in a third implantation process, implanting dopant atoms of the first doping type into the first surface,
• wherein the first implantation process comprises implanting the dopant atoms of the first doping type at a first implantation dose,
• wherein the second implantation process comprises implanting the dopant atoms of the second doping type at a second implantation dose,
• wherein the third implantation process comprises implanting the dopant atoms of the first doping type at a third implantation dose different from the second dopant dose,
• wherein the second implantation dose at least approximately equals the first dopant dose,
• wherein the third implantation dose is selected from between 40% and 60% of the first implantation dose, and
• wherein the first width, the second width, a width of mask regions that remain after forming the second openings, and the second and third implantation dose are adapted to one another such that
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• where w202 denotes the first width, w204 denotes the second width, w203 denotes a width of the mask regions that remain after forming the second openings, D2 denotes the second implantation dose, and D3 denotes the third implantation dose.