Method for producing a semiconductor device with a vertical dielectric layer

A method for producing a semiconductor device, comprising:

• providing a semiconductor body having a first surface;
• producing a first trench having a bottom and sidewalls and extending from the first surface into the semiconductor body;
• forming a dielectric layer along at least one sidewall of the trench;
• and
• filling the trench with a filling material,
• wherein forming the dielectric layer comprises:
• forming a protection layer on the least one sidewall such that the protection layer leaves a section of the at least one sidewall uncovered;
• oxidizing the semiconductor body in the region of the uncovered sidewall section to form a first section of the dielectric layer;
• and
• removing the protection layer,
• wherein the uncovered sidewall section adjoins the bottom and wherein forming the first section of the dielectric layer comprises:
• oxidizing the uncovered sidewall section and the bottom to form the first section of the dielectric layer and to form an oxide layer on the bottom;
• and
• removing the oxide layer from the bottom.

A method for producing a semiconductor device, comprising:

• providing a semiconductor body having a first surface;
• producing a first trench having a bottom and sidewalls and extending from the first surface into the semiconductor body;
• forming a dielectric layer along at least one sidewall of the trench;
• and
• filling the trench with a filling material,
• wherein forming the dielectric layer comprises:
• forming a protection layer on the least one sidewall such that the protection layer leaves a section of the at least one sidewall uncovered;
• oxidizing the semiconductor body in the region of the uncovered sidewall section to form a first section of the dielectric layer;
• removing the protection layer;
• forming a second section of the dielectric layer on the at least one sidewall;
• forming a sacrificial layer on the at least one sidewall after forming the first section of the dielectric layer;
• filling the first trench with the semiconductor material and at least partly removing the sacrificial layer so as to form a second trench;
• and
• filling the second trench with the second section of the dielectric layer.