Semiconductor device and manufacturing method thereof

A method for manufacturing a semiconductor device, comprising the steps of:

• preparing a semiconductor layer having a first surface and a second surface opposing each other;
• forming a trench gate in the semiconductor layer from a side of the first surface, so that the trench gate extends in a first direction parallel to the first surface and the second surface, and extends from the first surface to an interior of the semiconductor layer, and the trench gate has a gate open end distant from the second surface;
• forming a source material region of a first conductivity type and a channel region of a second conductivity type from the side of the first surface, so that orthographic projections of the source material region and the channel region on the second surface in a depth direction of the trench gate at least partially overlap with each other, and the source material region is farther from the second surface relative to the channel region;
• forming an insulating layer on a side of the source material region distant from the second surface, so that the source material region has a source open end distant from the second surface to form a source region, and the farther the source open end is from the second surface the smaller a width of the source open end in the second direction is, wherein the second direction is parallel to the first surface and the second surface, and the first direction is perpendicular to the second direction;
• and
• forming a contact trench from a side of the insulating layer distant from the second surface, so that the contact trench extends from the insulating layer to pass through the source open end to be in contact with the channel region in the depth direction of the trench gate.