초록

Lattice-mismatched epitaxial films formed proximate non-crystalline sidewalls. Embodiments of the invention include formation of facets that direct dislocations in the films to the sidewalls.

대표청구항 ▼

1. A method for forming a structure, the method comprising the steps of: providing a crystalline semiconductor substrate comprising a first semiconductor material and having a top surface;defining an opening having a non-crystalline sidewall proximate the top surface of the crystalline semiconductor

1. A method for forming a structure, the method comprising the steps of: providing a crystalline semiconductor substrate comprising a first semiconductor material and having a top surface;defining an opening having a non-crystalline sidewall proximate the top surface of the crystalline semiconductor substrate; andforming an epitaxial film in the opening, the epitaxial film comprising a second semiconductor material and including a growth front, the growth front including a surface comprising a facet not parallel to the substrate top surface, the second semiconductor material being lattice-mismatched to the first semiconductor material, wherein a dislocation in the epitaxial film propagates in a first direction within 10° of normal to the facet, the dislocation intersecting the non-crystalline sidewall in the first direction. 2. The method of claim 1, wherein the non-crystalline sidewall comprises a dielectric sidewall. 3. The method of claim 2 wherein the opening is defined in a dielectric material disposed over the top surface of the substrate. 4. The method of claim 1, wherein the facet defines an angle α with the top surface of the substrate, and an aspect ratio H of a height h of the opening to a width w of the opening is greater than or equal to (tan α+1/tan α)/2, wherein the height h is in a direction normal to the top surface of the crystalline semiconductor substrate, and the width w is in a direction parallel to the top surface of the crystalline semiconductor substrate. 5. The method of claim 4, wherein the height h is selected from the range of 0.05 μm to 5 μm. 6. The method of claim 1, wherein the opening comprises a trench. 7. The method of claim 1 wherein the dislocation in the epitaxial film is no more than about 8° off normal to the epitaxial film surface. 8. The method of claim 1, wherein the first semiconductor material comprises a group IV element or compound and the second semiconductor material comprises at least one of a group IV element or compound, a III-V compound, or a II-VI compound. 9. The method of claim 8, wherein the first semiconductor material comprises at least one of germanium or silicon. 10. The method of claim 8, wherein the second semiconductor material comprises the III-V compound and the III-V compound includes at least one of AlP, GaP, InP, AlAs, GaAs, InAs, AlSb, GaSb, InSb, AlN, GaN, InN, or their ternary or quaternary compounds. 11. The method of claim 1, wherein the non-Crystalline sidewall of the opening has a sloped profile. 12. A method for forming a structure, the method comprising the steps of: defining an opening in a dielectric material disposed over a crystalline semiconductor substrate comprising a first semiconductor material; andforming an epitaxial film in the opening, the epitaxial film (i) comprising a second semiconductor material lattice-mismatched to the first semiconductor material, and (ii) including a growth front having a surface, a dislocation in the epitaxial film propagating in a direction within 10° of perpendicular to the growth front surface, the dislocation terminating at a sidewall of the opening and with a termination angle defined in part by the direction within 10° of perpendicular to the growth front surface, wherein the growth front surface defines an acute angle α with a top surface of the substrate such that the epitaxial film growth front surface is substantially non-parallel to a top surface of the substrate, and an aspect ratio H of a height h of the opening to a width w of the opening is greater than or equal to (tan α+1/tan α)/2, wherein the height h is in a direction normal to the top surface of the substrate, and the width w is in a direction parallel to the top surface of the substrate. 13. The method of claim 12 wherein the opening defines a trench having a length at least twice the width w. 14. The method of claim 13, wherein the length of the trench is at least 6 mm. 15. The method of claim 12, wherein the trench has a width of less than 400 nm. 16. The method of claim 12, wherein the substrate is off-cut by up to about 6°. 17. The method of claim 12, wherein the second semiconductor material comprises a first layer grown at a first set of processing conditions, and a second layer disposed over the first layer and grown at a second set of processing conditions. 18. The method of claim 17, wherein the first layer is grown at a first temperature and the second layer is grown over the first layer at a second temperature, the second temperature being higher than the first temperature. 19. The method of claim 12, wherein the first semiconductor material comprises a group IV material and the second semiconductor material comprises a III-V compound. 20. The method of claim 19, wherein the III-V compound comprises a cubic structure. 21. A method for forming a structure; the method comprising the steps of: defining a trench having a longitudinal axis and a dielectric sidewall disposed adjacent a substrate comprising a first semiconductor material; andepitaxially growing a second semiconductor material in the trench, the second semiconductor material being lattice mismatched to the first semiconductor material,wherein defects arising from the lattice mismatch between the first and second semiconductor materials propagate away from the longitudinal axis of the trench in a direction substantially perpendicular to a growth front of the second material and are trapped by a sidewall of the trench, wherein the defects intersect the sidewall in the direction substantially perpendicular to the growth front. 22. A method for forming a structure, the method comprising the steps of: performing a selective etch to expose a crystal plane of a crystalline substrate including a first semiconductor material;forming a dielectric layer over the substrate;defining an opening in the dielectric layer to reveal the exposed crystal plane; andforming a second semiconductor material in the opening, wherein dislocations propagate away from a center of the opening in a plane approximately normal to a growth surface of the second semiconductor material, the dislocations terminating at a sidewall of the opening, the dislocations terminating at an angle defined by the plane approximately normal to the growth surface and the sidewall of the opening.