Method for increasing the performance of trenched devices and the resulting structure
AssigneeSiliconix Incorporated
InventorRichard A. Blanchard
Life of this patent
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Abstract
A trenched device, such as a DMOS transistor, provides for higher breakdown voltages than possible using trenched devices of the prior art. The trench extends only into the epitaxial layer, thereby minimizing breakdown problems associated with prior art trench devices in which the trench extends into the more highly doped substrate. However, in order to achieve higher breakdown voltages, the dopant concentration is increased in that portion of the epitaxial layer surrounding the bottom of the trench. Thus, a novel trenched device is taught which achieves higher breakdown voltages by causing the trench to be surrounded by relatively highly doped material, while not requiring the trench to extend into the more highly doped substrate itself.
Claims8
A semiconductor device comprising:
- a first region of semiconductor material, doped to a first concentration with a dopant of a first conductivity type, and serving as a drain region;
- a trench formed within said first region, said trench having sides and a bottom;
- a second region of semiconductor material located within said first region and adjacent to said trench near said bottom of said trench, said second region being of said first conductivity type and having a higher dopant concentration than said first region;
- a gate electrode within said trench;
- a layer of gate dielectric insulating said gate electrode from said first and second regions;
- a source region formed on the surface of said first semiconductor region;
- and
- a body region within said first region beneath said source region, said body region having a second conductivity type opposite said first conductivity type.
Dependencies are inferred from the claim text.