Solar cell, method of making, and photovoltaic module

A solar cell, comprising:

• a substrate, having a first surface and a second surface opposite to the first surface;
• a plurality of first doped portions, on the first surface;
• a plurality of second doped portions on the first surface, wherein the plurality of second doped portions and the plurality of first doped portions are alternatingly distributed on the first surface along a first direction, and doping elements in the plurality of first doped portions are of a first type and doping elements in the plurality of second doped portions are of a second type different from the first type;
• and
• a plurality of isolation trenches, wherein a respective isolation trench of the plurality of isolation trenches is formed between a respective first doped portion of the plurality of first doped portions and an adjacent second doped portion of the plurality of second doped portions, wherein the respective isolation trench has opposing first sidewall and second sidewall that extend along a second direction, at least one of the first sidewall and the second sidewall has a corrugated structure that undulates while extending along the second direction, and the second direction intersects with the first direction,
• wherein at least one of the first sidewall and the second sidewall transitions to a top surface of the respective first doped portion or a top surface of the adjacent second doped portion via a rounded corner,
• wherein a ratio of a height of the rounded corner along a thickness direction of the substrate to a height of the first sidewall along the thickness direction of the substrate is less than or equal to 3:20.