Fin Spacer Protected Source and Drain Regions in FinFETs
First Claim
1. A method comprising:
- etching a semiconductor substrate to form a first plurality of recesses;
filling the first plurality of recesses to form Shallow Trench Isolation (STI) regions, wherein a portion of the semiconductor substrate between the STI regions forms a semiconductor strip, wherein edges of the semiconductor strip contact sidewalls of the STI regions;
replacing a top portion of the semiconductor strip with a first semiconductor layer and a second semiconductor layer, wherein the second semiconductor layer is formed over the first semiconductor layer, wherein the first semiconductor layer has a first germanium percentage higher than a second germanium percentage of the second semiconductor layer;
recessing the STI regions, wherein a portion of the semiconductor strip with edges exposed by the recessed STI regions forms a semiconductor fin;
forming a gate stack over a middle portion of the semiconductor fin;
forming gate spacers on sidewalls of the gate stack;
forming fin spacers on sidewalls of an end portion of the semiconductor fin;
recessing the end portion of the semiconductor fin; and
growing an epitaxial region over the end portion of the semiconductor fin that is recessed.
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Accused Products
Abstract
A method includes forming Shallow Trench Isolation (STI) regions in a semiconductor substrate and a semiconductor strip between the STI regions. The method also include replacing a top portion of the semiconductor strip with a first semiconductor layer and a second semiconductor layer over the first semiconductor layer. The first semiconductor layer has a first germanium percentage higher than a second germanium percentage of the second semiconductor layer. The method also includes recessing the STI regions to form semiconductor fins, forming a gate stack over a middle portion of the semiconductor fin, and forming gate spacers on sidewalls of the gate stack. The method further includes forming fin spacers on sidewalls of an end portion of the semiconductor fin, recessing the end portion of the semiconductor fin, and growing an epitaxial region over the end portion of the semiconductor fin.
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Citations
20 Claims
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1. A method comprising:
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etching a semiconductor substrate to form a first plurality of recesses; filling the first plurality of recesses to form Shallow Trench Isolation (STI) regions, wherein a portion of the semiconductor substrate between the STI regions forms a semiconductor strip, wherein edges of the semiconductor strip contact sidewalls of the STI regions; replacing a top portion of the semiconductor strip with a first semiconductor layer and a second semiconductor layer, wherein the second semiconductor layer is formed over the first semiconductor layer, wherein the first semiconductor layer has a first germanium percentage higher than a second germanium percentage of the second semiconductor layer; recessing the STI regions, wherein a portion of the semiconductor strip with edges exposed by the recessed STI regions forms a semiconductor fin; forming a gate stack over a middle portion of the semiconductor fin; forming gate spacers on sidewalls of the gate stack; forming fin spacers on sidewalls of an end portion of the semiconductor fin; recessing the end portion of the semiconductor fin; and growing an epitaxial region over the end portion of the semiconductor fin that is recessed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of forming a Fin Field-Effect Transistor (FinFET) device, the method comprising:
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forming a first and a second semiconductor fin over a substrate, the first and second semiconductor fins being parallel to each other; forming Shallow Trench Isolation (STI) regions surrounding the first and the second semiconductor fins, wherein top portions of the first and the second semiconductor fins comprise a first epitaxial layer and a second epitaxial layer, with the first epitaxial layer underlying the second epitaxial layer and having a first germanium percentage; forming a gate stack over respective middle portions of the first and the second semiconductor fins; forming a fin spacer between end portions of the first and the second semiconductor fins, wherein the end portions of the first and the second semiconductor fins are disposed on a same side of the gate stack, wherein the fin spacer extends continuously on a first sidewall of the first semiconductor fin, a top surface of the STI regions, and a second sidewall of the second semiconductor fin, and wherein an edge of the fin spacer on the first sidewall has a first height larger than a second height of the fin spacer measured at a point midway between the first and the second semiconductor fins; removing top portions of the second epitaxial layer from the respective end portions of first and the second semiconductor fins; and epitaxially growing a first source/drain region and a second source/drain region over remaining portions of the second epitaxial layer of the end portions of the first and the second semiconductor fins, respectively. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method of forming a Fin Field-Effect Transistor (FinFET) device, the method comprising:
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forming a first and a second semiconductor fin over a substrate, with Shallow Trench Isolation (STI) regions surrounding the first and the second semiconductor fins, wherein top portions of the first and the second semiconductor fins comprise a germanium-containing first semiconductor layer and a substantially germanium-free second semiconductor layer, with the first semiconductor layer underlying the second semiconductor layer; forming a gate stack over middle portions of the first and the second semiconductor fins; forming fin spacers on sidewalls of end portions of the first and the second semiconductor fins, wherein top ends of the fins spacers extend above a top surface of the first semiconductor layer; removing top portions of the second semiconductor layer, and subsequently, epitaxially growing source/drain regions over the end portions of the first and the second semiconductor fins; removing the gate stack to expose the first and the second semiconductor layers in the middle portions of the first and the second semiconductor fins; and oxidizing outer portions of the first semiconductor layer. - View Dependent Claims (20)
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Specification