Method for fabricating FinFETs and semiconductor structure fabricated using the method
View Patent ↗A method for fabricating FinFETs is described. A semiconductor substrate is patterned to form odd fins. Spacers are formed on the substrate and on the sidewalls of the odd fins, wherein each spacer has a substantially vertical sidewall. Even fins are then formed on the substrate between the spacers. A semiconductor structure for forming FinFETs is also described, which is fabricated using the above method.
1. A method for fabricating fin-type field-effect transistors (FinFETs), comprising:
patterning a semiconductor substrate to form a plurality of odd fins of the FinFETs comprising a first semiconductor material;
forming a plurality of spacers on the substrate and on sidewalls of the odd fins of the FinFETs, wherein each of the spacers has a substantially vertical sidewall; and
forming, in presence of the spacers, a plurality of even fins of the FinFETs comprising a second semiconductor material on the substrate between the spacers.
2. The method of claim 1 , wherein forming the spacers comprises:
forming a substantially conformal material layer over the substrate;
performing, to the material layer, an anisotropic treatment that partially changes etching selectivity of the material layer; and
selectively etching the material layer.
3. The method of claim 2 , wherein the anisotropic treatment comprises an ion-implantation process.
4. The method of claim 3 , wherein the material layer comprises silicon nitride, the ion-implantation process implants carbon ions in the material layer, and the selective etching utilizes phosphoric acid.
5. The method of claim 2 , wherein the anisotropic treatment comprises a plasma treatment.
6. The method of claim 2 , wherein forming the substantially conformal material layer comprises an atomic layer deposition (ALD) process.
7. The method of claim 2 , wherein forming the substantially conformal material layer comprises a furnace deposition process.
8. The method of claim 2 , wherein forming the odd fins comprises:
forming, on the substrate, a patterned mask layer having patterns of the odd fins; and
patterning the substrate using the patterned mask layer as a mask.
9. The method of claim 1 , wherein forming the even fins comprises an epitaxy process.
10. The method of claim 9 , wherein the odd fins comprise Si and the even fins comprise SiC or SiGe.
11. The method of claim 9 , wherein the odd fins and the even fins comprise Si.
12. The method of claim 1 , wherein the even fins are different from the odd fins in at least one of height, width and material.
13. The method of claim 1 , wherein the spacers are formed on the substrate and on sidewalls of the odd fins without using a patterning mask.