Multi-gate device and method of fabrication thereof
First Claim
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1. A method of semiconductor device fabrication, comprising:
- forming a fin extending from a substrate, the fin having a source/drain region and a channel region, wherein the fin includes a first epitaxial layer having a first composition and a second epitaxial layer on the first epitaxial layer, the second epitaxial layer having a second composition, and a third epitaxial layer having the first composition over the second epitaxial layer wherein the forming the fin further includes forming an oxidized epitaxial layer that is disposed in the channel region and the source/drain region, wherein the oxidized epitaxial layer underlies the first source/drain feature;
forming a dummy gate structure over the channel region of the fin;
after forming the dummy gate structure, removing the second epitaxial layer from the source/drain region of the fin to form a gap extending from the first epitaxial layer to the third epitaxial layer;
depositing a spacer layer on sidewalls of the dummy gate structure and filling the gap such that a dielectric material of the spacer layer extends continuously from a top surface of the first epitaxial layer to a bottom surface of the third epitaxial layer and continuously along a length of source/drain region; and
while the spacer layer is filled within the gap, growing a source/drain epitaxial material on at least two surfaces of the first epitaxial layer to form a first source/drain feature on the fin.
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Abstract
A method of semiconductor device fabrication is described that includes forming a fin extending from a substrate and having a source/drain region and a channel region. The fin includes a first epitaxial layer having a first composition and a second epitaxial layer on the first epitaxial layer, the second epitaxial layer having a second composition. The second epitaxial layer is removed from the source/drain region of the fin to form a gap. The gap is filled with a dielectric material. Another epitaxial material is formed on at least two surfaces of the first epitaxial layer to form a source/drain feature.
44 Citations
20 Claims
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1. A method of semiconductor device fabrication, comprising:
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forming a fin extending from a substrate, the fin having a source/drain region and a channel region, wherein the fin includes a first epitaxial layer having a first composition and a second epitaxial layer on the first epitaxial layer, the second epitaxial layer having a second composition, and a third epitaxial layer having the first composition over the second epitaxial layer wherein the forming the fin further includes forming an oxidized epitaxial layer that is disposed in the channel region and the source/drain region, wherein the oxidized epitaxial layer underlies the first source/drain feature; forming a dummy gate structure over the channel region of the fin; after forming the dummy gate structure, removing the second epitaxial layer from the source/drain region of the fin to form a gap extending from the first epitaxial layer to the third epitaxial layer; depositing a spacer layer on sidewalls of the dummy gate structure and filling the gap such that a dielectric material of the spacer layer extends continuously from a top surface of the first epitaxial layer to a bottom surface of the third epitaxial layer and continuously along a length of source/drain region; and while the spacer layer is filled within the gap, growing a source/drain epitaxial material on at least two surfaces of the first epitaxial layer to form a first source/drain feature on the fin. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 19, 20)
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11. A method of fabricating a multi-gate device, the method comprising:
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forming a bottom epitaxial layer; growing an epitaxial layer stack including first, second, and third epitaxial layers over the bottom epitaxial layer; oxidizing the bottom epitaxial layer to form an oxide layer; removing the second epitaxial layer in a first region and a second region of the epitaxial layer stack to form a space between the first and third epitaxial layers; depositing a dielectric material in the space, wherein the first and second regions are interposed by a third region of the epitaxial layer stack, wherein the third region underlies a dummy gate structure, wherein a thickness of the oxide layer is greater than the thickness of the dielectric material; and forming a metal gate structure disposed on multiple sides of each of the first and third epitaxial layers in the third region of the epitaxial layer stack. - View Dependent Claims (12, 13, 14, 15)
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16. A method of semiconductor device fabrication, comprising:
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forming a fin extending from a substrate, the fin including a first epitaxial layer having a first composition and a second epitaxial layer on the first epitaxial layer, the second epitaxial layer having a second composition, and a third epitaxial layer having the first composition over the second epitaxial layer; removing the second epitaxial layer from a source/drain region of the fin to form a first gap extending from the first epitaxial layer to the third epitaxial layer while protecting a channel region of the fin; depositing a dielectric material within the first gap, wherein the depositing the dielectric material within the first gap includes; depositing a blanket layer of the dielectric material over a top surface of the third epitaxial layer, and etching the blanket layer to remove the dielectric material from the top surface of the third epitaxial layer and remove the dielectric material from a portion of a top surface of the first epitaxial layer; while the dielectric material is within the first gap, growing a source/drain epitaxial material on at least two surfaces of the first epitaxial layer to form a first source/drain feature on the fin; while the dielectric material is within the first gap, forming an interlayer dielectric (ILD) layer over the source/drain epitaxial material; providing a trench in the ILD layer to expose the channel region of the fin; and removing the second epitaxial layer within the trench to provide a second gap. - View Dependent Claims (17, 18)
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Specification