Trench MOS rectifier with termination structure

A manufacturing method for a semiconductor structure, the method comprising:

• forming on a substrate, at intervals in a first direction, a first trench, a second trench, and a third trench extending from a second surface towards a first surface opposite the second surface, wherein a cell region and a terminal region seen in a plan view are defined on the substrate, the first trench and the second trench being provided in the cell region, and the third trench being provided in the terminal region;
• forming a first oxide layer in the first trench, forming a second oxide layer in the second trench, and forming a third oxide layer in the third trench;
• forming a first semiconductor material layer in the first trench to cause the first semiconductor material layer to be surrounded by the first oxide layer to form a first trench structure, forming a second semiconductor material layer in the second trench to cause the second semiconductor material layer to be surrounded by the second oxide layer to form a second trench structure, and forming a third semiconductor material layer in the third trench to cause the third semiconductor material layer to be surrounded by the third oxide layer to form a third trench structure;
• forming a mask layer on the cell region, the first trench structure, and the second trench structure;
• performing a first etching process on the mask layer to form a first opening and a second opening, the first opening extending in the first direction such that at least part of the first semiconductor material layer is exposed, and the second opening extending in a second direction perpendicular to the first direction such that at least part of the second surface and the first trench structure are exposed;
• after the first etching process, performing a second etching process at the second opening to form a third surface on the substrate and to cause the first trench structure and the second trench structure to at least partially protrude from the third surface of the cell region;
• and
• forming a first doped region adjacent to the third surface exposed by the second opening, wherein when seen in a plan view, the first doped region is provided between the first trench structure and the second trench structure, and extends in the second direction.