Abstract: A high density trench power-MOSFET is described in the present invention. The power-MOSFET has a substrate, first and second epi-layers sequentially formed over the substrate and a trench type gate electrode. A silicon nitride layer is formed over the gate electrode to prevent an electrical connecting between the gate electrode and the metal layer formed in a later process.

Abstract: A high density trench power MOSFET is described in the present invention. The power-MOSFET has a substrate, first and second epi-layers sequentially formed over the substrate and a trench type gate electrode. A silicon nitride layer is formed over the gate electrode to prevent an electrical connecting between the gate electrode and the metal layer formed in a later process.

Abstract: A method of fabricating trench power MOSFET is described. A first etching step is performed on a substrate to form a plurality of trenches and the substrate has a first doped region and a second doped region and serves as a drain region. A gate oxide layer and a polysilicon layer are then sequentially formed on the second doped region to create a gate region. Subsequent performance of a second etching step utilizes a mask layer to overlap the polysilicon layer. A portion of the second doped region is exposed and the exposed portion defines a base region. The polysilicon layer is etched to expose the gate oxide layer and the base region is simultaneously etched to remove a portion of the second doped region to expose the first doped region for forming an aligned source region. A contact region in the source region is finally formed to fabricate the trench power MOSFET.