FinFET and manufacturing method of the same

A FinFET manufacturing method comprising:

• providing a transistor precursor that comprises:
• a semiconductor substrate comprising a plurality of insulating areas;
• a fin structure disposed to extend on the semiconductor substrate between two of the insulating areas;
• a gate dielectric layer disposed to extend across two sides of the fin structure;
• and
• a gate electrode structure disposed on the gate dielectric layer;
• performing etching on a first position and a second position of the fin structure, wherein the first position is at a first side of the fin structure relative to the gate electrode structure and the second position is at a second side of the fin structure relative to the gate electrode structure;
• and
• forming a drain structure at the first position and forming a source structure at the second position;
• forming a trench between the gate electrode structure and the first position of the fin structure without contacting the gate structure and the drain structure, and the trench has a depth relative to a height of the fin structure, wherein the height of the fin structure is relative to the semiconductor substrate, and the depth of the trench is smaller than or equal to the height of the fin structure such that the drain structure has a first resistance relative to the gate electrode and the source structure has a second resistance relative to the gate electrode, and the first resistance is larger than the second resistance.