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US 12,666,658 B2Granted
Buried shield structures for power semiconductor devices and related fabrication methods
AssigneeWolfspeed, Inc.
InventorsMadankumar Sampath, Sei-Hyung Ryu, Daniel Jenner Lichtenwalner, Woongsun Kim, Naeem Islam
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Abstract
A semiconductor device includes a semiconductor layer structure having a drift region of a first conductivity type and a well region of a second conductivity type above the drift region. A gate is provided on the semiconductor layer structure adjacent the well region. A buried shielding structure of the second conductivity type is provided under the well region and separated from the well region by a portion of the drift region. Related devices and fabrication methods are also discussed.
Claims41
A semiconductor device, comprising:
- a semiconductor layer structure comprising a drift region of a first conductivity type and a well region of a second conductivity type above the drift region;
- a gate on the semiconductor layer structure adjacent the well region;
- at least one contact shielding structure of the second conductivity type vertically extending into the drift region and laterally spaced apart from the gate;
- a bottom shielding structure of the second conductivity type under the gate;
- and
- a buried shielding structure of the second conductivity type under the well region and separated therefrom by a portion of the drift region,
- wherein the buried shielding structure laterally extends from the bottom shielding structure to the at least one contact shielding structure.
4 more elements
A semiconductor device, comprising:
- a semiconductor layer structure comprising a drift region of a first conductivity type and a well region of a second conductivity type above the drift region;
- a gate on the semiconductor layer structure adjacent the well region;
- a buried shielding structure of the second conductivity type under the well region and separated therefrom by a portion of the drift region;
- and
- a drain contact on the semiconductor layer structure below the drift region,
- wherein the buried shielding structure comprises segments that extend in a first lateral direction and the gate extends in a second lateral direction that is different from the first lateral direction,
- wherein the segments are laterally spaced apart such that at least a part of an electrical conduction path between the well region and the drain contact laterally extends along the buried shielding structure in the second lateral direction.
4 more elements
A semiconductor device, comprising:
- a semiconductor layer structure comprising:
- a drift region of a first conductivity type;
- a buried shielding structure of a second conductivity type in the drift region;
- a well region of the second conductivity type above the drift region;
- and
- a source region of the first conductivity type above the well region;
- and
- a source contact on a surface of the semiconductor layer structure, wherein the source contact is electrically coupled to the source region and to the buried shielding structure,
- wherein the source region, the well region, and a first portion of the drift region between the well region and the buried shielding structure provide p-n junctions of a first transistor, and
- wherein the first portion of the drift region, the buried shielding structure, and a second portion of the drift region provide p-n junctions of a second transistor.
7 more elements
A semiconductor device, comprising:
- a semiconductor layer structure comprising a first surface and a second surface opposite the first surface;
- a gate adjacent the first surface of the semiconductor layer structure;
- a drain contact on the second surface of the semiconductor layer structure;
- a source contact on the first surface of the semiconductor layer structure, wherein the source contact is electrically coupled to a source region of a first conductivity type and a buried shielding structure of a second conductivity type in the semiconductor layer structure;
- and
- first and second transistors in the semiconductor layer structure and electrically coupled in a cascode amplifier configuration between the first and second surfaces thereof.
3 more elements
A method of fabricating a semiconductor device, the method comprising:
- providing a drift region of a first conductivity type;
- providing a buried shielding structure of a second conductivity type in the drift region;
- providing a well region of the second conductivity type above the drift region and separated from the buried shielding structure, wherein the drift region, the buried shielding structure, and the well region form a semiconductor layer structure;
- providing a bottom shielding structure of the second conductivity type;
- providing at least one contact shielding structure of the second conductivity type vertically extending into the drift region;
- and
- providing a gate on the semiconductor layer structure adjacent the well region,
- wherein the bottom shielding structure is under the gate, the at least one contact shielding structure is laterally spaced apart from the gate, and the buried shielding structure laterally extends from the bottom shielding structure to the at least one contact shielding structure.
5 more elements
Dependencies are inferred from the claim text.