Method of making a heteroepitaxial layer on a seed area
A method for making a heteroepitaxial layer. The method comprises providing a semiconductor substrate. A seed area delineated with a selective growth mask is formed on the semiconductor substrate. The seed area comprises a first material and has a linear surface dimension of less than 100 nm. A heteroepitaxial layer is grown on the seed area, the heteroepitaxial layer comprising a second material that is different from the first material. Devices made by the method are also disclosed.
1. A method for making a heteroepitaxial layer, the method comprising:
providing a semiconductor substrate;
forming a nanostructured pedestal on the semiconductor substrate, the pedestal having a top surface and a side surface, the top surface forming a seed area having a linear surface dimension that ranges from about 10 nm to about 100 nm;
providing a selective growth mask layer on the top surface and side surface of the pedestal;
removing a portion of the selective growth mask layer to expose the seed area of the pedestal;
selectively etching back the exposed top surface of the pedestal; and
growing a heteroepitaxial layer on the seed area.
2. The method of claim 1 , wherein the linear surface dimension is less than 25 nm.
3. The method of claim 1 , wherein the seed area comprises a (001) plane of single crystal Si and the heteroepitaxial layer comprises a material chosen from a Group III-V semiconductor material or germanium.
4. The method of claim 1 , wherein the semiconductor substrate comprises silicon having a [001] direction normal to the substrate surface.
5. The method of claim 1 , wherein providing the selective growth mask comprises oxidizing a surface of the pedestal.
6. The method of claim 1 , wherein removing the portion of the selective growth mask layer to expose the seed area comprises etching the insulator to expose a (001) plane of the silicon material.
7. The method of claim 1 , wherein the selectively etching back of the pedestal results in formation of sidewall barriers from the selective growth mask layer that extends above the surface of the remaining pedestal.
8. The method of claim 7 , wherein removing the portion of the selective growth mask layer comprises: forming a non-conformal layer over the selective growth mask layer; and etching the non-conformal layer and the selective growth mask layer to expose the (001) facet.
9. The method of claim 1 , wherein the heteroepitaxial layer comprises a Group III-V semiconductor material.
10. The method of claim 1 , wherein removing the portion of the selective growth mask layer comprises: forming a non-conformal layer over the selective growth mask layer; and etching the non-conformal layer and the selective growth mask layer to expose the (001) facet.