Fin structure with varying isolation thickness
First Claim
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1. A method of forming a semiconductor structure comprising:
- depositing a first nitride layer on a semiconductor structure comprising a first fin and a second fin;
removing a portion of the first nitride layer to form nitride spacer regions on a lower sidewall portion of the first fin and a lower sidewall portion of the second fin;
removing the nitride spacer regions from the first fin;
depositing an oxide region on the semiconductor structure;
recessing the oxide region;
depositing a second nitride layer over the semiconductor structure;
removing a portion of the second nitride layer to form nitride spacer regions on an upper sidewall portion of the first fin and an upper sidewall portion of the second fin;
forming an isolation region under the first fin by performing a thermal oxidation; and
removing the nitride spacer regions from the upper sidewall portion of the first fin and the upper sidewall portion of the second fin.
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Abstract
Semiconductor fins having isolation regions of different thicknesses on the same integrated circuit are disclosed. Nitride spacers protect the lower portion of some fins, while other fins do not have spacers on the lower portion. The exposed lower portion of the fins are oxidized to provide isolation regions of different thicknesses.
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Citations
18 Claims
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1. A method of forming a semiconductor structure comprising:
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depositing a first nitride layer on a semiconductor structure comprising a first fin and a second fin; removing a portion of the first nitride layer to form nitride spacer regions on a lower sidewall portion of the first fin and a lower sidewall portion of the second fin; removing the nitride spacer regions from the first fin; depositing an oxide region on the semiconductor structure; recessing the oxide region; depositing a second nitride layer over the semiconductor structure; removing a portion of the second nitride layer to form nitride spacer regions on an upper sidewall portion of the first fin and an upper sidewall portion of the second fin; forming an isolation region under the first fin by performing a thermal oxidation; and removing the nitride spacer regions from the upper sidewall portion of the first fin and the upper sidewall portion of the second fin. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of forming a semiconductor structure comprising:
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depositing a first nitride layer on a semiconductor structure comprising a first fin and a second fin; removing a portion of the first nitride layer to form nitride spacer regions on a lower sidewall portion of the first fin and a lower sidewall portion of the second fin; removing the nitride spacer regions from the first fin; depositing a first oxide region on the semiconductor structure; recessing the first oxide region to a level below the top of the first fin and second fin, and above the nitride spacer regions on the lower sidewall portion of the second fin; depositing a second nitride layer over the semiconductor structure; removing a portion of the second nitride layer to form nitride spacer regions on an upper sidewall portion of the first fin and an upper sidewall portion of the second fin; depositing a second oxide region on the semiconductor structure; forming an isolation region under the first fin and under the second fin by performing a thermal oxidation; removing the second oxide region from the semiconductor structure; and removing the nitride spacer regions from the upper sidewall portion of the first fin and the upper sidewall portion of the second fin. - View Dependent Claims (13, 14, 15)
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16. A semiconductor structure, comprising:
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a semiconductor substrate; a first fin formed in the semiconductor substrate; a second fin formed in the semiconductor substrate; wherein a first oxide region is disposed below the first fin; and wherein a second oxide region is disposed below the second fin; and wherein the first oxide region is thicker than the second oxide region; a fin portion disposed below the second oxide region, wherein the fin portion is in direct physical contact with the semiconductor substrate; nitride spacers disposed adjacent to the fin portion. - View Dependent Claims (17, 18)
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Specification