Method for manufacturing mosfet device and mosfet device thereof

A method for manufacturing a metal-oxide-semiconductor field-effect transistor (MOSFET) device with a single-crystal substrate as an epitaxial region, comprising steps:

• S110:
• providing a substrate with high resistivity;
• S120:
• forming trenches on the substrate by photolithography and etching, wherein the trenches comprise gate interconnection trenches, active region gate trenches, and voltage-withstand ring trenches;
• S130:
• forming gate interconnection structures respectively in the gate interconnection trenches, forming trench gates respectively in the active region gate trenches, and forming voltage-withstand rings respectively in the voltage-withstand ring trenches;
• S140:
• performing first ion implantation and first high-temperature activation to form a body region, and performing second ion implantation and second high-temperature activation to form a source region;
• S150:
• depositing an isolation layer, and forming gate interconnection metal contacts, source region metal contacts, and a cut-off ring metal contact on the isolation layer;
• wherein the gate interconnection metal contacts, the source region metal contacts, and the cut-off ring metal contact run through the isolation layer;
• wherein the gate interconnection metal contacts are respectively connected to the gate interconnection structures, the source region metal contacts are connected to the source region, and the cut-off ring metal contact is connected to one of the voltage-withstand rings farthest away from the gate interconnection structure;
• S160:
• performing metallization deposition on the isolation layer, and forming bonding pads by photolithography and etching, wherein the bonding pads comprise a gate metal connected to the gate interconnection metal contacts, a source metal connected to the source region contacts, and a cut-off ring metal connected to the cut-off ring contacts;
• wherein the gate metal, the source metal and the cut-off ring metal are isolated from each other;
• and
• S180:
• thinning the substrate from a back surface thereof, and forming a drain metal on the back surface of the substrate.