Metal semiconductor field effect transistors (MESFETS) having channels of varying thicknesses and related methods
AssigneeCree, Inc.
InventorSaptharishi Sriram
Life of this patent
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Abstract
A unit cell of a metal-semiconductor field-effect transistor (MESFET) is provided. The unit cell includes a MESFET having a source, a drain and a gate. The gate is between the source and the drain and on a channel layer of the MESFET. The channel layer has a first thickness on a source side of the channel layer and a second thickness, thicker than the first thickness, on a drain side of the channel layer. Related methods of fabricating MESFETs are also provided herein.
Claims23
A unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising:
- a MESFET having a source, a drain and a gate, the gate being between the source and the drain and on a channel layer of the MESFET, the channel layer having a first thickness on a source side of the channel layer and a second thickness, thicker than the first thickness, on a drain side of the channel layer;
- and
- a recess between the source and the drain that exposes the channel layer, the recess having a first depth on a source side of the recess that defines the first thickness of the channel layer and a second depth on a drain side of the recess that defines the second thickness of the channel, the gate being disposed in the recess, wherein the first depth is from about 700 Å to about 2200 Å and the second depth is from about 500 Å to about 1500 Å.
A unit cell of a silicon carbide (SiC) metal-semiconductor field-effect transistor (MESFET), comprising:
- a SiC MESFET having a source, a drain and a gate, the gate being between the source and the drain and on a SiC channel layer of the MESFET, the SiC channel layer having a first thickness on a source side of the SiC channel layer and a second thickness, thicker than the first thickness, on a drain side of the SiC channel layer;
- and
- a recess between the source and the drain that exposes the SiC channel layer, the recess having a first depth on a source side of the recess that defines the first thickness of the SiC channel layer and a second depth on a drain side of the recess that defines the second thickness of the SiC channel, the gate being disposed in the recess, wherein the first depth is from about 700 Å to about 2200 Å and the second depth is from about 500 Å to about 1500 Å.
A method of forming a unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising:
- forming a MESFET having a source, a drain and a gate, the gate being between the source and the drain and on a channel layer of the MESFET, the channel layer having a first thickness on a source side of the channel layer and a second thickness, thicker than the first thickness, on a drain side of the channel layer,
- wherein the channel layer defines a recess between the source and the drain that exposes the channel layer, the recess having a first depth on a source side of the recess that defines the first thickness of the channel layer and a second depth on a drain side of the recess that defines the second thickness of the channel, the gate being disposed in the recess;
- and
- wherein the first depth is from about 700 Å to about 2200 Å and the second depth is from about 500 Å to about 1500 Å.
Dependencies are inferred from the claim text.