Bulk nanosheet with dielectric isolation
First Claim
1. A method of forming a nanowire field effect transistor (FET) device, the method comprising the steps of:
- forming a plurality of nanosheets as a stack on a bulk semiconductor wafer, wherein the plurality of nanosheets comprises alternating layers of a sacrificial material and a channel material as the stack on the bulk semiconductor wafer;
patterning the nanosheets to form one or more nanowire stacks and one or more trenches between the nanowire stacks;
forming spacers covering sidewalls of the nanowire stacks;
oxidizing a top portion of the bulk semiconductor wafer through the trenches, wherein the oxidizing step forms a dielectric isolation region in the top portion of the bulk semiconductor wafer;
removing the spacers;
selectively removing portions of the layers of the sacrificial material from the nanowire stacks in a channel region of the FET device releasing portions of the channel material from the nanowire stacks, wherein the portions of the channel material released from the nanowire stacks form nanowire channels of the FET device, and wherein a first layer in the nanowire stacks comprises the sacrificial material and is present on the bulk semiconductor wafer; and
forming a gate surrounding the nanowire channels in the channel region of the FET device, wherein the first layer in the nanowire stacks has an inverted triangular shape beneath the gate in the channel region of the FET device.
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Abstract
Techniques for dielectric isolation in bulk nanosheet devices are provided. In one aspect, a method of forming a nanosheet device structure with dielectric isolation includes the steps of: optionally implanting at least one dopant into a top portion of a bulk semiconductor wafer, wherein the at least one dopant is configured to increase an oxidation rate of the top portion of the bulk semiconductor wafer; forming a plurality of nanosheets as a stack on the bulk semiconductor wafer; patterning the nanosheets to form one or more nanowire stacks and one or more trenches between the nanowire stacks; forming spacers covering sidewalls of the nanowire stacks; and oxidizing the top portion of the bulk semiconductor wafer through the trenches, wherein the oxidizing step forms a dielectric isolation region in the top portion of the bulk semiconductor wafer. A nanowire FET and method for formation thereof are also provided.
18 Citations
5 Claims
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1. A method of forming a nanowire field effect transistor (FET) device, the method comprising the steps of:
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forming a plurality of nanosheets as a stack on a bulk semiconductor wafer, wherein the plurality of nanosheets comprises alternating layers of a sacrificial material and a channel material as the stack on the bulk semiconductor wafer; patterning the nanosheets to form one or more nanowire stacks and one or more trenches between the nanowire stacks; forming spacers covering sidewalls of the nanowire stacks; oxidizing a top portion of the bulk semiconductor wafer through the trenches, wherein the oxidizing step forms a dielectric isolation region in the top portion of the bulk semiconductor wafer; removing the spacers; selectively removing portions of the layers of the sacrificial material from the nanowire stacks in a channel region of the FET device releasing portions of the channel material from the nanowire stacks, wherein the portions of the channel material released from the nanowire stacks form nanowire channels of the FET device, and wherein a first layer in the nanowire stacks comprises the sacrificial material and is present on the bulk semiconductor wafer; and forming a gate surrounding the nanowire channels in the channel region of the FET device, wherein the first layer in the nanowire stacks has an inverted triangular shape beneath the gate in the channel region of the FET device. - View Dependent Claims (2, 3, 4, 5)
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Specification