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US 2004/0175889 A1Published application
High density trench power MOSFET structure and fabrication method thereof
AssigneeAdvanced Power Electronics Corp.
InventorsLin-Chung Huang, Keh-Yuh Yu
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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.
Claims21
A method of forming a high-density trench power-MOSFET structure, said method comprising the following steps of:
- forming a first dielectric layer on a substrate, wherein said first dielectric layer and said substrate are identical in polarity;
- forming a second dielectric layer on said first dielectric layer, wherein said first dielectric layer and said second dielectric layer have are opposite in polarity;
- forming a trench structure in said substrate, wherein said trench structure penetrates said second dielectric layer;
- forming a gate oxide layer on an outer surface of said trench structure;
- forming a first conducting layer to fill said trench structure to serve as a gate structure, wherein a top surface of said first conducting layer is lower than a top surface of said second dielectric layer;
- forming a third dielectric layer on said gate structure, wherein a top surface of said third dielectric layer and a top surface of said second dielectric layer form a plane;
- forming a first doped region in said second dielectric layer to serve as a deep body region, wherein said first doped region and said second dielectric layer are identical in polarity;
- forming a second doped region in said second dielectric layer to serve as a source region, wherein said second doped region is next to sidewalls of said trench structure and said second doped region and said first dielectric layer are identical in polarity;
- forming a fourth dielectric layer to cover said third dielectric layer;
- and
- forming a second conducting layer on said fourth dielectric layer and said second dielectric layer.
8 more elements
A high-density trench power-MOSFET structure, said structure comprising:
- a first dielectric layer located on a substrate, wherein said first dielectric layer and said substrate are identical in polarity;
- a second dielectric layer locating on said first dielectric layer, wherein said first dielectric layer and said second dielectric layer are opposite in polarity;
- a trench structure located in said substrate, wherein said trench structure penetrates said second dielectric layer;
- a gate oxide layer located on an outer surface of said trench structure;
- a first conducting layer filling said trench structure to serve as a gate structure, wherein a top surface of said first conducting layer is lower than a top surface of said second dielectric layer;
- a third dielectric layer locating on said gate structure, wherein a top surface of said third dielectric layer and a top surface of said second dielectric layer form a plane;
- a doped region next to sidewalls of said trench structure to serve as a source region, wherein said doped region and said first dielectric layer are identical in polarity;
- a fourth dielectric layer located on said third dielectric layer;
- and
- a second conducting layer located on said fourth dielectric layer and said second dielectric layer.
7 more elements
Dependencies are inferred from the claim text.