Split electrode gate trench power device
View Patent ↗A power semiconductor device which includes gate liners extending along gate insulation liners and an insulation block spacing the two gate liners.
1. A power semiconductor device, comprising: a semiconductor body including a drift region of one conductivity, and a base region of another conductivity; a gate trench extending at least through said base region; gate insulation liner lining at least the sidewalls of said gate trench; a gate electrode adjacent each said gate insulation liner; an insulation block interposed between said gate electrodes and adjacent each gate electrode; a conductive regions of said one conductivity adjacent said gate trench; and a first power electrode electrically connected to said conductive regions; and a connector connecting said gate electrodes, wherein said connector is proud of said semiconductor body, is not wider than said gate trench, and includes a silicided top portion.
2. The device of claim 1 , wherein said device is a power MOSFET.
3. The device of claim 1 , further comprising an insulation body at the bottom of said gate trench, said insulation body being thicker than said gate insulation liners.
4. The device of claim 3 , wherein said gate insulation liners, said insulation block, and said insulation body are comprised of an oxide.
5. The device of claim 1 , further comprising a substrate of said one conductivity, said semiconductor body being disposed on said substrate and further comprising a second power electrode electrically connected to said substrate.
6. The device of claim 5 , wherein said first power electrode is a source electrode, said second power electrode is a drain electrode, and said conductive regions are source regions.
7. The device of claim 1 , wherein said sidewalls of said gate trench are tapered.
8. A method of fabricating a power semiconductor device, comprising:
forming a trench mask that includes and opening over a semiconductor body that includes a drift region and a base region adjacent said drift region;
forming a trench at bottom of said opening that extends through said base region;
oxidizing at least the sidewalls of said trench to form gate liners adjacent said sidewalls;
covering said oxidized sidewalls with an electrically conductive material to form gate electrodes;
depositing an insulation block between said gate liners electrodes and adjacent each gate liner electrode;
depositing conductive material inside said open to link said gate electrodes with a conductive connector, said conductive connector extending above said semiconductor body;
and removing said trench mask to obtain a conductive connector that is proud of said semiconductor body.
9. The method of claim 8 , further comprising forming an insulation body at the bottom of said trench, said insulation body being thicker than said gate liners.
10. The method of claim 8 , said conductive material comprises conductive polysilicon.
11. The method of claim 8 , wherein said gate liners are proud of said semiconductor body.
12. The method of claim 8 , further comprising siliciding a top portion of said connector.