Termination structure for trench DMOS device and method of making the same
1 Assignment
0 Petitions
Accused Products
Abstract
Embodiments of the present invention are directed to a termination structure provided for a trench DMOS device to reduce occurrence of current leakage resulting from electric field crowding at the border of the active area and a method of manufacturing the same. In one embodiment, the termination structure for the trench DMOS device comprises a substrate of a first type conductivity and an epitaxial layer of the first type conductivity over the substrate. The epitaxial layer has a lower doping concentration than the substrate. A body region of a second type conductivity is provided within the epitaxial layer. A trench extends through the body region between an active area and an edge of the substrate. A gate oxide layer lines the trench and extends to the upper surface of the body region between the trench and the active area. A passivation layer is formed on the gate oxide layer, including sidewalls and a bottom surface of the trench. A metal layer covers portions of the passivation layer on the side walls of the trench to expose a part of the passivation layer over the bottom surface of the trench.
-
Citations
26 Claims
-
1. (canceled)
-
2. (canceled)
-
3. (canceled)
-
4. (canceled)
-
5. (canceled)
-
6. (canceled)
-
7. (canceled)
-
8. (canceled)
-
9. (canceled)
-
10. (canceled)
-
11. (canceled)
-
12. (canceled)
-
13. A method of simultaneously forming a trench DMOS device and a termination structure provided therefor, comprising:
-
forming an epitaxial layer of a first type conductivity on a substrate of said first type conductivity, said epitaxial layer having a greater doping concentration than said substrate;
forming a body region of a second type conductivity within said epitaxial layer;
forming a plurality of first type trenches and a second type trench through said body region, said second type trench having a greater width than said first type trenches;
growing a gate oxide layer for covering said body region and lining said first type trenches and said second type trench;
filling said first type trenches with gate electrode;
forming a plurality of doped regions of said first type conductivity within said body region between said first type trenches;
forming a passivation layer on said gate oxide layer and covering said gate electrode;
forming a plurality of contact holes between said first type trenches;
forming a plurality of contact regions of a second type conductivity within exposed portions of said body region in said first type trenches;
forming a metal layer on said passivation layer and filling said contact holes and said second type trench; and
forming an opening through said metal layer to expose a part of said passivation layer over a bottom surface of said second type trench, and portions of said passivation layer on side walls of said second type trench being covered by said metal layer. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
-
24. (canceled)
-
25. (canceled)
-
26. (canceled)
Specification