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US 2011/0254088 A1Published application
Power MOSFET With Embedded Recessed Field Plate and Methods of Fabrication
AssigneeMaxPower Semiconductor, Inc.
InventorsMohamed N. Darwish, Jun Zeng, Shih-Tzung Su, Richard A. Blanchard
Life of this patent
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Abstract
Semiconductor power devices, and related methods, wherein a recessed contact makes lateral ohmic contact to the source diffusion, but is insulated from the underlying recessed field plate (RFP). Such an insulated RFP is here referred to as an embedded recessed field plate (ERFP).
Claims23
A power semiconductor device, comprising:
- a semiconductor source region, which is heavily doped with a first conductivity type;
- a semiconductor body region, which has a second conductivity type and is located at least partially beneath said source region;
- a first trench which extends through said source and body regions, and includes at least one gate electrode which is capacitively coupled to at least part of said body region;
- and
- a second trench which is at least as deep as said first trench, and which contains a field plate covered by an insulator, said second trench extending down through the body region into a first-conductivity-type semiconductor drift region which is more lightly doped than the source region;
- a recessed metallic source contact overlying said field plate, but separated therefrom at active device locations by said insulator, and making ohmic contact to said source region;
- wherein, at said active device locations, the top of said field plate is deeper than the top of said gate electrode, and the bottom of said field plate is deeper than the bottom of said gate electrode;
- whereby said gate electrode can invert at least part of the body region to permit passage of majority carriers from the source region through the inverted part of the body region into the drift region, and the majority carriers can pass through the drift region into a first-conductivity-type drain region.
5 more elements
A power semiconductor device, comprising:
- a source region having a first conductivity type;
- a body region, which has a second conductivity type and is located at least partially beneath said source region;
- a first-conductivity-type drain region, and a first-conductivity-type drift region which separates said drain region from said body;
- a first trench which extends through said source and body regions, and includes at least one gate electrode which is capacitively coupled to at least part of said body region;
- and
- a second trench which is at least as deep as said first trench, and which contains a field plate;
- wherein the field plate is covered by an insulator at least some active device locations;
- wherein a shielding portion of said drift region, below said second trench, contains a lower net concentration of first-conductivity-type dopant atoms than said drift region generally;
- and wherein, at said active device locations, the top of said field plate is deeper than the top of said gate electrode, and the bottom of said field plate is deeper than the bottom of said gate electrode;
- whereby said gate electrode can invert at least part of the body region to permit passage of majority carriers from the source region through the inverted part of the body region into the drift region, and the majority carriers can pass through the drift region into a first-conductivity-type drain region.
7 more elements
-33. (canceled)
A power semiconductor device, comprising:
- a first trench which includes at least one gate electrode;
- a source region, which is heavily doped with a first conductivity type;
- a second-conductivity-type body region in proximity to said first trench, said gate electrode being capacitively coupled to a portion of said body region;
- and
- a second trench containing a recessed field plate covered by an insulator, said second trench extending down through the body region into a first-conductivity-type semiconductor drift region which is more lightly doped than the source region;
- and
- a recessed source contact overlying said recessed field plate, but separated therefrom by said insulator, and making ohmic contact to said source region;
- whereby said gate electrode can invert at least part of the body region to permit passage of majority carriers from the source region through the inverted part of the body region into the drift region, and the majority carriers can pass through the drift region into a drain region.
5 more elements
-128. (canceled)
Dependencies are inferred from the claim text.