Super junction structure

Abstract

A super junction structure includes a substrate, wherein the substrate has a first conductivity type. The super junction structure includes an epitaxial layer over the substrate, wherein the epitaxial layer has a second conductivity type opposite the first conductivity type. The super junction structure further includes a bury layer between the epitaxial layer and the substrate, wherein the bury layer has the second conductivity type. The super junction structure further includes a conductive pillar in the epitaxial layer, wherein the conductive pillar has the first conductivity type, sidewalls of the conductive pillar are angled with respect to a top-most surface of the epitaxial layer, a bottom surface of the conductive pillar is rounded, and a top-most surface of the conductive pillar is coplanar with the top-most surface of the epitaxial layer.

What is claimed is: 
     
         1 . A super junction structure comprising:
 a substrate, wherein the substrate has a first conductivity type;   an epitaxial layer over the substrate, wherein the epitaxial layer has a second conductivity type opposite the first conductivity type;   a bury layer between the epitaxial layer and the substrate, wherein the bury layer has the second conductivity type; and   a conductive pillar in the epitaxial layer, wherein the conductive pillar has the first conductivity type, sidewalls of the conductive pillar are angled with respect to a top-most surface of the epitaxial layer, a bottom surface of the conductive pillar is rounded, and a top-most surface of the conductive pillar is coplanar with the top-most surface of the epitaxial layer.   
     
     
         2 . The super junction structure of  claim 1 , wherein the conductive pillar comprises a polymer material. 
     
     
         3 . The super junction structure of  claim 1 , wherein the first conductivity type comprises p-type. 
     
     
         4 . The super junction structure of  claim 1 , further comprising a gate trench, wherein the conductive pillar is below the gate trench. 
     
     
         5 . The super junction structure of  claim 1 , further comprising a doped well, wherein the conductive pillar is below the doped well. 
     
     
         6 . A super junction structure comprising:
 a substrate, wherein the substrate has a first conductivity type;   an epitaxial layer over the substrate, wherein the epitaxial layer has a second conductivity type opposite the first conductivity type; and   a conductive pillar in the epitaxial layer, wherein the conductive pillar has the first conductivity type, sidewalls of the conductive pillar are angled with respect to a top-most surface of the epitaxial layer, and a bottom surface of the conductive pillar is rounded.   
     
     
         7 . The super junction structure of  claim 6 , further comprising a bury layer between the epitaxial layer and the substrate. 
     
     
         8 . The super junction structure of  claim 7 , wherein the bury layer has the second conductivity type. 
     
     
         9 . The super junction structure of  claim 6 , wherein a top-most surface of the conductive pillar is coplanar with the top-most surface of the epitaxial layer. 
     
     
         10 . The super junction structure of  claim 6 , further comprising a gate trench over the conductive pillar. 
     
     
         11 . The super junction structure of  claim 6 , further comprising a doped well over the conductive pillar. 
     
     
         12 . The super junction structure of  claim 6 , further comprising a second conductive pillar in the epitaxial layer. 
     
     
         13 . The super junction structure of  claim 12 , wherein a portion of the epitaxial layer is between the conductive pillar and the second conductive pillar. 
     
     
         14 . A super junction structure comprising:
 a substrate, wherein the substrate has a first conductivity type;   an epitaxial layer over the substrate, wherein the epitaxial layer has a second conductivity type opposite the first conductivity type; and   a plurality of conductive pillars in the epitaxial layer, wherein each of the plurality of conductive pillars has the first conductivity type, a distance between adjacent conductive pillars of the plurality of conductive pillars increases as a distance from a top surface of the epitaxial layer increases, and a bottom surface of a first conductive pillar of the plurality of conductive pillars is rounded.   
     
     
         15 . The super junction structure of  claim 14 , wherein sidewalls of the first conductive pillar are angled with respect to the top surface of the epitaxial layer. 
     
     
         16 . The super junction structure of  claim 15 , wherein sidewalls of a second conductive pillar of the plurality of conductive pillars are angled with respect to the top surface of the epitaxial layer. 
     
     
         17 . The super junction structure of  claim 14 , further comprising a gate trench above the first conductive pillar. 
     
     
         18 . The super junction structure of  claim 14 , further comprising a doped well above the first conductive pillar. 
     
     
         19 . The super junction structure of  claim 14 , wherein a portion of the epitaxial layer is between the adjacent conductive pillars. 
     
     
         20 . The super junction structure of  claim 14 , further comprising a buried layer between the substrate and the epitaxial layer, wherein the buried layer is below each of the plurality of conductive pillars.