FORMING A FIN USING DOUBLE TRENCH EPITAXY
First Claim
1. A method comprising:
- forming a first dielectric layer on a substrate;
partially removing the first dielectric layer exposing an upper surface of the substrate, and forming a lower trench extending across a length of the substrate;
filling the lower trench and forming a second dielectric layer on the first dielectric layer;
forming a third dielectric layer on the second dielectric layer;
removing one or more portions of the third dielectric layer down to the second dielectric layer to form one or more upper trenches, leaving a remaining portion of the third dielectric layer above the lower trench and having a width greater than a width of the lower trench;
completely removing the second dielectric layer exposing the first dielectric layer and exposing the upper surface of the substrate;
forming an epitaxial layer on the upper surface of the substrate and on the first dielectric layer, the epitaxial layer filling the lower trench and the one or more upper trenches up to a height above an upper surface of the third dielectric layer; and
removing the epitaxial layer above the upper surface of the third dielectric layer, making an upper surface of the epitaxial layer substantially flush with the upper surface of the third dielectric layer.
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Accused Products
Abstract
The present invention relates generally to semiconductor devices and more particularly, to a structure and method of forming a fin using double trench epitaxy. The fin may be composed of a III-V semiconductor material and may be grown on a silicon, silicon germanium, or germanium substrate. A double trench aspect ratio trapping (ART) epitaxy method may trap crystalline defects within a lower trench (i.e. a defective region) and may permit formation of a fin free of patterning defects in an upper trench (i.e. a fin mold). Crystalline defects within the defective region may be trapped via conventional aspect ratio trapping or three-sided aspect ratio trapping. Fin patterning defects may be avoided by utilizing a fin mold to grow an epitaxial fin and selectively removing dielectric material adjacent to a fin region.
4 Citations
20 Claims
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1. A method comprising:
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forming a first dielectric layer on a substrate; partially removing the first dielectric layer exposing an upper surface of the substrate, and forming a lower trench extending across a length of the substrate; filling the lower trench and forming a second dielectric layer on the first dielectric layer; forming a third dielectric layer on the second dielectric layer; removing one or more portions of the third dielectric layer down to the second dielectric layer to form one or more upper trenches, leaving a remaining portion of the third dielectric layer above the lower trench and having a width greater than a width of the lower trench; completely removing the second dielectric layer exposing the first dielectric layer and exposing the upper surface of the substrate; forming an epitaxial layer on the upper surface of the substrate and on the first dielectric layer, the epitaxial layer filling the lower trench and the one or more upper trenches up to a height above an upper surface of the third dielectric layer; and removing the epitaxial layer above the upper surface of the third dielectric layer, making an upper surface of the epitaxial layer substantially flush with the upper surface of the third dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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forming a first dielectric layer on a substrate; partially removing the first dielectric layer exposing an upper surface of the substrate, and forming a lower trench extending across a length of the substrate; filling the lower trench and forming a second dielectric layer on the first dielectric layer; forming a third dielectric layer on the second dielectric layer; forming a hardmask on a portion of the third dielectric layer so that the exposed portion of the third dielectric layer runs perpendicular to the lower trench; removing the exposed portion of the third dielectric layer, an exposed portion of the second dielectric layer, and an exposed portion of the first dielectric layer down to the upper surface of the substrate; forming a support layer on the upper surface of the substrate, the support layer having a height extending at least to an upper surface of the third dielectric layer; removing the hardmask; removing one or more portions of the third dielectric layer down to the second dielectric layer to form one or more upper trenches, leaving a remaining portion of the third dielectric layer above the lower trench and having a width greater than a width of the lower trench; removing the second dielectric layer exposing the first dielectric layer and exposing the upper surface of the substrate; forming an epitaxial layer on the upper surface of the substrate and on the first dielectric layer, the epitaxial layer filling the lower trench and the one or more upper trenches up to a height above the upper surface of the third dielectric layer; and removing the epitaxial layer above the upper surface of the third dielectric layer so that an upper surface of the epitaxial layer is substantially flush with the upper surface of the third dielectric layer. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A structure comprising:
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a first dielectric layer on an upper surface of a substrate, wherein a lower trench extends a length of the substrate exposing a first upper surface of the substrate and a sidewall on one or more portions of the first dielectric layer, wherein the lower trench is surrounded by the first upper surface of the substrate at a bottom, a sidewall of a first dielectric layer at two sides, an opening between the first dielectric layer and a third dielectric layer at two sides above the sidewall, and a defect trapping surface of the third dielectric layer at a top; a support layer on a second upper surface of the substrate, wherein a length of the support layer is perpendicular to the length of the lower trench; and a third dielectric layer contacting, and anchored to, a sidewall of the support layer, the third dielectric layer above, but not contacting, the first dielectric layer leaving the opening between the first dielectric layer and the third dielectric layer, wherein one or more upper trenches extend through the third dielectric layer down to the opening between the first dielectric layer and the third dielectric layer, wherein the one or more upper trenches are above the first dielectric layer but not above the lower trench. - View Dependent Claims (18, 19, 20)
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Specification