Abstract
The invention provides a structure of a trench metal-oxide-semiconductor field-effect transistor, comprising: a metal layer disposed on a top surface and a bottom surface of the structure respectively; an N-type semiconductor substrate disposed on the drain; an N-drift region disposed on the N-type semiconductor substrate; an N-current spread layer (N-CSL) disposed on the N-drift region; a P-welldisposed on the N-CSL; an N-type semiconductor layer disposed on the P-well; a first P-type semiconductor layer adjacent to the N-type semiconductor layer and disposed on the P-well; a trench extending through the N-type semiconductor layer, the P-well and the N-CSL; an insulating layer disposed in the trench; a split gate disposed in the insulating layer of the trench and covered by the insulating layer; a gate disposed in the insulating layer of the trench and above the split gate; and a semiconductor protection layer disposed below the bottom of the trench and adjacent to the N-drift region, wherein the insulating layer is disposed above the semiconductor protection layer to protect the insulating layer from being broken; wherein the gate and the split gate are separated from each otherby the insulating layer to form a predetermined gap.