Transistor device and manufacturing method thereof

A manufacturing method of a transistor device, comprising:

• providing a first conductive type epitaxial layer disposed on a substrate;
• using a first mask to implant second conductive type ions into the first conductive type epitaxial layer to form a second conductive type body region;
• using a second mask to implant first conductive type ions into the second conductive type body region to form a first conductive type heavily doped region in the second conductive type body region;
• forming a self-aligned sidewall on the sidewalls of the second mask;
• using the self-aligned sidewall to etch and remove a portion of the first conductive type heavily doped region and a portion of the second conductive type body region to form a recess structure disposed on the second conductive type body region, while simultaneously forming two self-aligned first conductive type heavily doped regions self-aligned on the upper edges of both sides of the recess structure;
• and
• implanting second conductive type ions into the recess structure to form a second conductive type heavily doped recess.