FIN ISOLATION FOR MULTIGATE TRANSISTORS
First Claim
1. A method for fabricating a multigate transistor device comprising:
- providing a substrate including a semiconductor upper layer and a lower layer beneath the upper layer, wherein the lower layer has a rate of transformation into a dielectric that is higher than a rate of transformation into a dielectric of the upper layer when the upper and lower layers are subjected to dielectric transformation conditions;
forming fins in the upper layer;
transforming, after said forming, the lower layer beneath the fins into a dielectric material by germanium condensation of at least a portion of the lower layer to electrically isolate the fins; and
forming a gate structure over the fins to complete the multigate transistor device.
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Accused Products
Abstract
Multigate transistor devices and methods of their fabrication are disclosed. In one method, a substrate including a semiconductor upper layer and a lower layer beneath the upper layer is provided. The lower layer has a rate of transformation into a dielectric that is higher than a rate of transformation into a dielectric of the upper layer when the upper and lower layers are subjected to dielectric transformation conditions. Fins are formed in the upper layer, and the lower layer beneath the fins is transformed into a dielectric material to electrically isolate the fins. In addition, a gate structure is formed over the fins to complete the multigate transistor device.
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Citations
20 Claims
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1. A method for fabricating a multigate transistor device comprising:
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providing a substrate including a semiconductor upper layer and a lower layer beneath the upper layer, wherein the lower layer has a rate of transformation into a dielectric that is higher than a rate of transformation into a dielectric of the upper layer when the upper and lower layers are subjected to dielectric transformation conditions; forming fins in the upper layer; transforming, after said forming, the lower layer beneath the fins into a dielectric material by germanium condensation of at least a portion of the lower layer to electrically isolate the fins; and forming a gate structure over the fins to complete the multigate transistor device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for fabricating a multigate transistor device comprising:
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forming recesses in a lower layer that is beneath a semiconductor upper layer in which fins are formed, wherein the recesses are disposed between the fins of the upper layer; transforming the recessed lower layer beneath the fins into a first dielectric material to electrically isolate the fins; forming, after the transforming, a second dielectric material in the recesses such that top surfaces of regions of the first dielectric material that are beneath the fins are higher than top surfaces of the second dielectric material; and forming a gate structure over the fins to complete the multigate transistor device. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for fabricating a multigate transistor device comprising:
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providing a substrate including a semiconductor upper layer and a lower layer beneath the upper layer, wherein the lower layer has a rate of transformation into a dielectric that is higher than a rate of transformation into a dielectric of the upper layer when the upper and lower layers are subjected to dielectric transformation conditions; forming recesses in the lower layer such that the recesses are disposed between the fins of the upper layer; transforming the recessed lower layer beneath the fins into a first dielectric material to electrically isolate the fins such that a width of a region of the first dielectric material beneath a given fin of said fins is at most equal to a width of the given fin; depositing a second dielectric material in the recesses; and forming a gate structure over the fins to complete the multigate transistor device. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification