Semiconductor structure and fabrication method thereof

A method for fabricating a semiconductor structure, comprising:

• providing a semiconductor substrate having a first region and a second region and having a plurality of first fins in the first region and a plurality of second fins in the second region;
• performing a first oxidation process on the plurality of first fins to form a first oxide layer on surfaces of the plurality of first fins, wherein corners between top surfaces and side surfaces of the plurality of first fins form first rounded corners;
• and
• performing a second oxidation process on the plurality of second fins to form a second oxide layer on surfaces of the plurality of second fins, wherein corners between top surfaces and side surfaces of the second fins form second rounded corners, wherein:
• a width of the first fin is smaller than a width of the second fin;
• and
• a radius of curvature of the first rounded corner is greater than a radius of curvature of the second rounded corner.

A method for fabricating a semiconductor structure, comprising:

• providing a semiconductor substrate having a first region and a second region and having a plurality of first fins in the first region and a plurality of second fins in the second region;
• performing a first oxidation process on the plurality of first fins to form a first oxide layer on surfaces of the plurality of first fins, wherein corners between top surfaces and side surfaces of the plurality of first fins form first rounded corners, wherein performing the first oxidation process on the plurality of first fins to form the first oxide layer comprises:
• performing the first oxidation process to the plurality of first fins to form a first initial oxide layer on the surfaces of the first fins and the second fins;
• and
• removing the first initial oxide layer in the second region to form the first oxide layer;
• and
• performing a second oxidation process on the plurality of second fins to form a second oxide layer on surfaces of the plurality of second fins, wherein corners between top surfaces and side surfaces of the second fins form second rounded corners,
• wherein a radius of curvature of the first rounded corner is different from a radius of curvature of the second rounded corner.