Trench type power transistor device

Abstract

The present invention provides a trench type power transistor device including a substrate, an epitaxial layer, a doped diffusion region, a doped source region, and a gate structure. The substrate, the doped diffusion region, and the doped source region have a first conductivity type, and the substrate has an active region and a termination region. The epitaxial layer is disposed on the substrate, and has a second conductivity type. The epitaxial layer has a through hole disposed in the active region. The doped diffusion region is disposed in the epitaxial layer at a side of the through hole, and is in contact with the substrate. The doped source region is disposed in the epitaxial layer disposed right on the doped diffusion region, and the gate structure is disposed in the through hole between the doped diffusion region and the doped source region.

What is claimed is: 
     
         1 . A trench type power transistor device, comprising:
 a substrate having a first conductivity type, wherein the substrate has an active region and a termination region;   an epitaxial layer disposed on the substrate and having a second conductivity type different from the first conductivity type, wherein the substrate has at least a first through hole and at least a second through hole respectively penetrating the epitaxial layer, the first through hole is located in the active region, and the second through hole is located in the termination region;   a first doped diffusion region disposed in the epitaxial layer at one side of the first through hole and in directly contact with the substrate, wherein the first doped diffusion region has the first conductivity type;   a doped source region disposed in the epitaxial layer and right above the first doped diffusion region, wherein the doped source region has the first conductivity type;   a gate structure disposed in the first through hole between the first doped diffusion region and the doped source region;   a second doped diffusion region disposed on one side of the second through hole in the epitaxial layer and in direct contact with the substrate, wherein the second doped diffusion region has the first conductivity type; and   a terminal conductive layer disposed in the second through hole right above the second doped diffusion region.   
     
     
         2 . The trench type power transistor device according to  claim 1 , further comprising a first isolation layer disposed in the first through hole below the gate structure, wherein the first isolation layer electrically isolates the first doped diffusion region from the gate structure. 
     
     
         3 . The trench type power transistor device according to  claim 1 , wherein the gate structure comprises a gate conductive layer and a gate dielectric layer, and the gate dielectric layer is disposed between the gate conductive layer and the epitaxial layer. 
     
     
         4 . The trench type power transistor device according to  claim 1 , further comprising a well disposed in the epitaxial layer above the first doped diffusion layer and the second doped diffusion layer, wherein the well has a second conductivity type. 
     
     
         5 . The trench type power transistor device according to  claim 1 , further comprising a second isolation layer located in the second through hole below the terminal conductive layer. 
     
     
         6 . The trench type power transistor device according to  claim 1 , wherein the first conductivity type is P-type and the second conductivity type is N-type.