Method for manufacturing a semiconductor body with a trench and semiconductor body with a trench

A method for manufacturing a semiconductor body with a trench, comprising the steps of:

• etching the trench in the semiconductor body by using an etching mask arrangement that features a polysilicon layer for etching the trench;
• forming a silicon oxide layer on at least one side wall of the trench and on a bottom of the trench by thermal oxidation;
• removing the silicon oxide layer on the bottom of the trench by using an additional etching mask arrangement having an additional silicon oxide layer produced from the polysilicon layer by means of thermal oxidation;
• and
• filling the trench with polysilicon in order to form a polysilicon body that is arranged directly on the silicon oxide layer and on a substrate material of the bottom,
• wherein the polysilicon layer is at least partially oxidized during the production of the silicon oxide layer on the at least one side wall of the trench, and, therefore is at least partially converted into the additional silicon oxide layer, and
• wherein a size of a recess in the additional etching mask arrangement is reduced in comparison to a size of a recess in the etching mask arrangement by the at least partial oxidation of the polysilicon layer during the production of the silicon oxide layer on the at least one side wall of the trench and on the bottom of the trench.

A method for manufacturing a semiconductor body with a trench, comprising the steps of

• etching the trench in the semiconductor body by using an etching mask arrangement that features a polysilicon layer for etching the trench;
• forming a silicon oxide layer on at least one side wall of the trench and on a bottom of the trench by thermal oxidation;
• removing the silicon oxide layer on the bottom of the trench by using an additional etching mask arrangement having an additional silicon oxide layer produced from the polysilicon layer by thermal oxidation;
• and
• filling the trench with polysilicon in order to form a polysilicon body that is arranged directly on the silicon oxide layer and on a substrate material of the bottom,
• wherein an undercut of the etching mask arrangement is produced during etching of the trench, and
• wherein a width of a recess of the trench is greater than a width of a recess of the etching mask arrangement.