Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication

1. A method of forming a structure, the method comprising:

providing a dielectric sidewall, on a substrate, with a height h, the substrate comprising a first crystalline semiconductor material and a top surface having a first crystal orientation, the dielectric sidewall defining an opening with a first width w exposing a portion of the substrate;

defining, in the exposed portion of the substrate, a recess with a maximum depth d and a recessed surface comprising a second crystal orientation, the recessed surface defining a second width of the recess at the top surface of the substrate and defining a third width of the recess at a depth below the top surface of the substrate, the second width being greater than the third width; and

forming, in the recess and adjoining the dielectric sidewall, a second crystalline semiconductor material having a lattice mismatch with the first crystalline semiconductor material, the lattice mismatch creating defects in the second crystalline semiconductor material, the defects terminating at a distance H above a deepest point of the recess, wherein H is less than or equal to h+d.

2. The method of claim 1 , wherein H is less than or equal to d.

3. A method of forming a structure, the method comprising:

providing a dielectric sidewall, on a substrate, with a height h, the substrate comprising a first crystalline semiconductor material and a top surface having a first crystal orientation, the dielectric sidewall defining an opening with a first width w exposing a portion of the substrate;

defining, in the exposed portion of the substrate, a recess with a maximum depth d and a recessed surface comprising a second crystal orientation, the recessed surface defining a second width of the recess at the top surface of the substrate and defining a third width of the recess at a depth below the top surface of the substrate, the second width being greater than the third width; and

forming, in the recess and adjoining the dielectric sidewall, a second crystalline semiconductor material having a lattice mismatch with the first crystalline semiconductor material, the lattice mismatch creating defects in the second crystalline semiconductor material, the defects terminating at a distance H above a deepest point of the recess, wherein H is less than or equal to w.

4. A method of forming a structure, the method comprising:

providing a dielectric sidewall, on a substrate, with a height h, the substrate comprising a first crystalline semiconductor material and a top surface having a first crystal orientation, the dielectric sidewall defining an opening with a first width w exposing a portion of the substrate;

defining, in the exposed portion of the substrate, a recess with a maximum depth d and a recessed surface comprising a second crystal orientation, the recessed surface defining a second width of the recess at the top surface of the substrate and defining a third width of the recess at a depth below the top surface of the substrate, the second width being greater than the third width; and

forming, in the recess and adjoining the dielectric sidewall, a second crystalline semiconductor material having a lattice mismatch with the first crystalline semiconductor material, the lattice mismatch creating defects in the second crystalline semiconductor material, the defects terminating at a distance H above a deepest point of the recess, wherein a ratio of h+d to w is greater than or equal to one.

5. A method of forming a structure, the method comprising:

providing a dielectric sidewall, on a substrate, with a height h, the substrate comprising a first crystalline semiconductor material and a top surface having a first crystal orientation, the dielectric sidewall defining an opening with a first width w exposing a portion of the substrate;

defining, in the exposed portion of the substrate, a recess with a maximum depth d and a recessed surface comprising a second crystal orientation, the recessed surface defining a second width of the recess at the top surface of the substrate and defining a third width of the recess at a depth below the top surface of the substrate, the second width being greater than the third width; and

forming, in the recess and adjoining the dielectric sidewall, a second crystalline semiconductor material having a lattice mismatch with the first crystalline semiconductor material, the lattice mismatch creating defects in the second crystalline semiconductor material, the defects terminating at a distance H above a deepest point of the recess, wherein the recess has a v-shaped profile.

6. A method of forming a structure, the method comprising:

providing a dielectric sidewall, on a substrate, with a height h, the substrate comprising a first crystalline semiconductor material and a top surface having a first crystal orientation, the dielectric sidewall defining an opening with a first width w exposing a portion of the substrate;

defining, in the exposed portion of the substrate, a recess with a maximum depth d and a recessed surface comprising a second crystal orientation, the recessed surface defining a second width of the recess at the top surface of the substrate and defining a third width of the recess at a depth below the top surface of the substrate, the second width being greater than the third width; and

forming, in the recess and adjoining the dielectric sidewall, a second crystalline semiconductor material having a lattice mismatch with the first crystalline semiconductor material, the lattice mismatch creating defects in the second crystalline semiconductor material, the defects terminating at a distance H above a deepest point of the recess, wherein the first crystal orientation is (100), and the second crystal orientation is not (100).

7. The method of claim 6 , wherein the second crystal orientation is (111).

8. A method of forming a structure, the method comprising:

forming an opening in a dielectric layer, the dielectric layer being over a substrate, the substrate comprising a first crystalline material, the opening exposing an exposed surface of a top surface of the substrate;

forming a recess in the substrate in the exposed surface, the recess having a recess sidewall that forms an obtuse angle with the top surface of the substrate; and

forming a second crystalline material in the recess and in the opening, the second crystalline material being lattice mismatched with the first crystalline material.

9. The method of claim 8 , wherein the lattice mismatch creates defects in the second crystalline material, the defects terminating at a distance above a deepest point of the recess, the distance being less than or equal to a height of the dielectric layer from the top surface of the substrate plus a maximum depth of the recess.

10. The method of claim 8 , wherein the lattice mismatch creates defects in the second crystalline material, the defects terminating at a distance above a deepest point of the recess, the distance being less than or equal to a maximum depth of the recess.

11. The method of claim 8 , wherein the lattice mismatch creates defects in the second crystalline material, the defects terminating at a distance above a deepest point of the recess, the distance being less than or equal to a width of the opening.

12. The method of claim 8 , wherein a ratio of a height of the dielectric layer from the top surface of the substrate plus a maximum depth of the recess to a width of the opening is greater than or equal to one.

13. The method of claim 8 , wherein the recess has a v-shaped profile.

14. The method of claim 8 , wherein the top surface of the substrate has a first crystal orientation of (100), and the recessed sidewall has a second crystal orientation of not (100).

15. The method of claim 14 , wherein the second crystal orientation is (111).