Metal-semiconductor field effect transistors (MESFETs) having drains coupled to the substrate and methods of fabricating the same
First Claim
1. A unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region, the source region to gate contact distance being from about 0.5 to about 0.7 μ
- m and the drain region to gate contact distance being from about 1.5 to about 2.0 μ
m and the drain region being electrically coupled to the substrate through a contact via hole to the substrate.
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Accused Products
Abstract
The present invention provides a unit cell of a metal-semiconductor field-effect transistor (MESFET). The unit cell of the MESFET includes a MESFET having a source region, a drain region and a gate contact. The gate contact is disposed between the source region and the drain region. The drain region is electrically coupled to the substrate through a contact via hole to the substrate. Related methods of fabricating MESFETs are also provided herein.
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Citations
66 Claims
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1. A unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region, the source region to gate contact distance being from about 0.5 to about 0.7 μ
- m and the drain region to gate contact distance being from about 1.5 to about 2.0 μ
m and the drain region being electrically coupled to the substrate through a contact via hole to the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
- m and the drain region to gate contact distance being from about 1.5 to about 2.0 μ
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25. A unit cell of a metal-semiconductor field-effect transistor(MESFET), comprising:
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a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the drain region being electrically coupled to the substrate through a contact via hole to the substrate; and an n-type conductivity channel layer on the substrate, the gate contact being disposed on the n-type conductivity layer, wherein the n-type conductivity channel layer comprises n-type conductivity silicon carbide (SiC), wherein the gate extends into the n-type conductivity SiC channel layer and wherein the gate contact is disposed in a double recess.
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26. A unit cell of a metal-semiconductor field-effect transistor(MESFET), comprising:
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a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the drain region being electrically coupled to the substrate through a contact via hole to the substrate; and an n-type conductivity channel layer on the substrate, the gate contact being disposed on the n-type conductivity layer, wherein the contact via hole comprises a first contact via hole, the unit cell further comprising; a p-type conductivity region beneath the source region and having an end that extends towards the drain region, the p-type conductivity region being spaced apart from the n-type conductivity channel layer and being electrically coupled to the source region; and a second contact via hole adjacent the source region that exposes the p-type conductivity region; and an ohmic contact on the exposed portion of the p-type conductivity region.
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27. A unit cell of a metal-semiconductor field-effect transistor(MESFET), comprising:
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a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the drain region being electrically coupled to the substrate through a contact via hole to the substrate; and an n-type conductivity channel layer on the substrate, the gate contact being disposed on the n-type conductivity layer, wherein the n-type conductivity channel layer comprises first, second and third n-type conductivity SiC channel layers and wherein the first, second and third n-type conductivity channel layers have respective first, second and third carrier concentrations.
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28. A unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising:
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a silicon carbide (SiC) MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the source region to gate contact distance being from about 0.5 to about 0.7 μ
m and the drain region to gate contact distance being from about 1.5 to about 2.0 μ
m; andfirst and second ohmic contacts on the source region and the drain region, respectively, that respectively define a source contact and a drain contact, the drain region being electrically coupled to the substrate through a contact via hole to the substrate. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method of forming a unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising forming a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region, the source region to gate contact distance being from about 0.5 to about 0.7 μ
- m and the drain region to gate contact distance being from about 1.5 to about 2.0 μ
m and the drain region being electrically coupled to the substrate through a contact via hole to the substrate. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
- m and the drain region to gate contact distance being from about 1.5 to about 2.0 μ
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63. A method of forming a unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising:
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forming a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the drain region being electrically coupled to the substrate through a contact via hole to the substrate; and forming an n-type conductivity channel layer on the substrate, the gate contact being disposed on the n-type conductivity layer, wherein forming the n-type conductivity channel layer comprises forming an n-type conductivity silicon carbide (SiC) channel layer, wherein the gate extends into the n-type conductivity SiC channel layer and wherein the gate contact is disposed in a double recess.
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64. A method of forming a unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising:
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forming a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the drain region being electrically coupled to the substrate through a contact via hole to the substrate; and forming an n-type conductivity channel layer on the substrate, the gate contact being disposed on the n-type conductivity layer, wherein the contact via hole comprises a first contact via hole, the method further comprising; forming a p-type conductivity region beneath the source region and having an end that extends towards the drain region, the p-type conductivity region being spaced apart from the n-type conductivity channel layer and being electrically coupled to the source region; and forming a second contact via hole adjacent the source region that exposes the p-type conductivity region; and forming an ohmic contact on the exposed portion of the p-type conductivity region.
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65. A method of forming a unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising:
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forming a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the drain region being electrically coupled to the substrate through a contact via hole to the substrate; forming an n-type conductivity channel layer on the substrate, the gate contact being disposed on the n-type conductivity layer; forming a first buffer layer on the substrate; and forming a second buffer layer on the first buffer layer, wherein the n-type conductivity channel layer is on the second buffer layer and wherein the contact via hole extends through the drain region, the n-type channel region and the first and second buffer layers to a first surface of the substrate, wherein forming the n-type conductivity channel layer comprises; forming first, second and third n-type conductivity SiC channel layers and wherein the first, second and third n-type conductivity channel layers have respective first, second and third carrier concentrations.
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66. A method of forming a unit cell of a metal-semiconductor field-effect transistor (MESFET), comprising:
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forming a MESFET on a substrate, the MESFET having a source region, a drain region and a gate contact, the gate contact being between the source region and the drain region and the drain region being electrically coupled to the substrate through a contact via hole to the substrate; and forming an n-type conductivity channel layer on the substrate, the gate contact being disposed on the n-type conductivity layer, wherein forming the contact via hole comprises; etching a contact window for the contact via hole in an oxide layer on the drain region; and etching the n-type conductivity channel layer, and first and second buffer layers through the contact window to expose the substrate.
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Specification