SiC MOSFET with built-in Schottky diode
AssigneeSemiconductor Components Industries, LLC
InventorAndrei Konstantinov
Life of this patent
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Abstract
A power SiC MOSFET with a built-in Schottky rectifier provides advantages of including a Schottky rectifier, such as avoiding bipolar degradation, while reducing a parasitic capacitive charge and related power losses, as well as system cost. A lateral built-in channel layer may enable lateral spacing of the MOSFET gate oxide from a high electric field at the Schottky contact, while also providing current limiting during short-circuit events.
Claims20
A Silicon Carbide (SiC) semiconductor device, comprising:
- an n-type substrate;
- a drift region disposed on the n-type substrate;
- a p-type body region disposed on the drift region;
- a vertical Junction Field Effect Transistor (JFET) region disposed on the drift region;
- a Schottky contact disposed over the p-type body region and the vertical JFET region;
- a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) having a source region electrically connected to the p-type body region and to the Schottky contact, a gate and gate oxide disposed at least partially on the p-type body region, and a drain contact electrically connected to the n-type substrate;
- and
- an n-type lateral channel layer at least partially overlapping the gate oxide, the Schottky contact, the p-type body region, and the vertical JFET region, and electrically connecting the MOSFET and the vertical JFET region.
A SiC semiconductor device, comprising:
- a substrate of a first conductivity type;
- a drift region disposed on the substrate;
- a junction field effect transistor (JFET) region of the first conductivity type, the JFET region being disposed on the drift region;
- a body region of a second conductivity type, the body region being disposed on the drift region and adjacent to the JFET region;
- a Schottky contact disposed over the JFET region and over a portion of the body region;
- a lateral channel layer of the first conductivity type, extending laterally over the body region and the JFET region, and partially adjacent to the Schottky contact;
- and
- a MOSFET having a source region of the first conductivity type that is electrically connected to the Schottky contact, a drain region of the first conductivity type, a gate, and a gate oxide disposed over the body region, the lateral channel layer, and the source region.
A method of making a SiC semiconductor device, the method comprising:
- providing a drift region on a SiC substrate of a first conductivity type;
- providing a body region of a second conductivity type on the drift region;
- providing a JFET region of the first conductivity type on the drift region and adjacent to the body region;
- providing a lateral channel layer of the first conductivity type, extending laterally across the body region and the JFET region;
- providing a Schottky contact laterally overlapping an entirety of the JFET region and a portion of the lateral channel layer;
- and
- providing a MOSFET having a source region electrically connected to the body region and to the Schottky contact, a gate and gate oxide disposed at least partially on the body region and on the lateral channel layer, and a drain contact electrically connected to the substrate.
Dependencies are inferred from the claim text.