1. A semiconductor structure comprising:
a trench located in a single crystalline semiconductor material layer;
a graded-doping semiconductor material portion located on sidewalls and a bottom surface of said trench and epitaxially aligned to said single crystalline semiconductor material layer, said graded-doping semiconductor material portion including a faceted surface that is inclined upwardly toward an edge of a vertical sidewall of said trench such that said faceted surface adjoins a topmost portion of said vertical sidewall at an edge and having a gradient in a dopant concentration; and
a doped semiconductor material portion located on said graded-doping semiconductor material portion and protruding above said trench and epitaxially aligned to said graded-doping semiconductor material portion, wherein said doped semiconductor material portion is spaced from said single crystalline semiconductor material layer by said graded-doping semiconductor material portion.
2. The semiconductor structure of claim 1, wherein said graded-doping semiconductor material portion includes a tapered region including said faceted surface, a uniform-width vertical portion having a first uniform width that is invariant under translation along a vertical direction, and a uniform-width horizontal portion having a second uniform width that is invariant under translation along a horizontal direction.
3. The semiconductor structure of claim 2, wherein said doped semiconductor material portion contacts said faceted surface, a vertical sidewall of said graded-doping semiconductor material portion, and a horizontal surface of said graded-doping semiconductor material portion.
4. The semiconductor structure of claim 1, wherein said gradient in said dopant concentration points toward an interface between said graded-doping semiconductor material portion and said doped semiconductor material portion.
5. The semiconductor structure of claim 1, wherein said faceted surface of said graded-doping semiconductor material portion orients along a {111} plane.
6. The semiconductor structure of claim 1, further comprising:
a gate stack contacting a top surface of said single crystalline semiconductor material layer; and
a gate spacer contacting and laterally surrounding said gate stack.
7. The semiconductor structure of claim 6, wherein said vertical sidewall of said trench is vertically coincident with a lower portion of a sidewall of said gate spacer.
8. The semiconductor structure of claim 7, wherein said faceted surface of said graded-doped semiconductor material portion and said sidewall of said gate spacer coincide at said edge.
9. The semiconductor structure of claim 8, wherein said doped semiconductor material portion is in contact with said lower portion of said sidewall of said gate spacer.
10. The semiconductor structure of claim 6, wherein said gate stack comprises a gate dielectric and a gate conductor.
11. The semiconductor structure of claim 6, further comprising a sourcedrain extension region located in said single crystalline semiconductor material layer underlying said gate spacer, said sourcedrain extension region having a vertical cross-sectional shape of a triangle and adjoining said graded-doping semiconductor material portion.
12. The semiconductor structure of claim 1, wherein said graded-doping semiconductor material portion and said doped semiconductor material portion are lattice-mismatched with respect to said single crystalline semiconductor material layer.
13. The semiconductor structure of claim 12, wherein said graded-doping semiconductor material portion and said doped semiconductor material portion apply a stress to a channel region of said single crystalline semiconductor material layer.
14. The semiconductor structure of claim 13, wherein said single crystalline semiconductor material layer comprises silicon, said graded-doping semiconductor material portion comprises a first silicon-germanium alloy, and said doped semiconductor material portion comprises a second silicon-germanium alloy that is the same as or different from said first silicon-germanium alloy.
15. The semiconductor structure of claim 13, wherein said single crystalline semiconductor material layer comprises silicon, wherein said graded-doping semiconductor material portion comprises a first silicon-carbon alloy, and said doped semiconductor material portion comprises a second silicon-carbon alloy that is the same as or different from said first silicon-carbon alloy.
16. The semiconductor structure of claim 1, further comprising a metal-semiconductor alloy portion located on a top surface of said doped semiconductor material portion.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
We claim:
1. An X-ray optical system for X-ray analysis of a sample, the system comprising:
a first graded multi-layer mirror;
an X-ray source for generating X-rays impingent on said first graded multi-layer mirror, said X-ray source having an extension Qx in an X-direction, perpendicular to a connecting line in a z-direction between said X-ray source and said first graded multi-layer mirror, which is larger than a region of acceptance of said first graded multi-layer mirror in a first focus of said first mirror in said x-direction; and
a first collimator disposed at said first focus between said X-ray source and said first mirror, said first collimator having a first opening in said x-direction corresponding to a region of acceptance of said first mirror, wherein a separation qzA between said first collimator and said X-ray source is given by qzAQxtan x, with x being an angle subtended by said first graded multi-layer mirror in said x-direction as seen from said first collimator.
2. The system of claim 1, further comprising a second graded multi-layer mirror, wherein an extension Qy of said X-ray source in a y direction, perpendicular to a connecting line in said z direction between said X-ray source and said second graded multi-layer mirror, is larger than a region of acceptance of said second mirror in a second focus of said second mirror in said y direction, and further comprising a second collimator disposed at said second focus of said second graded multi-layer mirror between said X-ray source and said second mirror, said second collimator having an opening in said y direction corresponding to a region of acceptance of said second graded multi-layer mirror, a separation qzB between said second collimator and said X-ray source being qzBQytan y, wherein y defines an angle subtended by said second graded multi-layer mirror in said y direction, as viewed from said second collimator.
3. The system of claim 2, wherein said x direction and said y direction are orthogonal.
4. The system of claim 2, wherein said first focus of said first graded multi-layer mirror coincides with said second focus of said second graded multi-layer mirror.
5. The system of claim 2, wherein said first focus of said first graded multi-layer mirror does not coincide with said second focus of said second graded multi-layer mirror.
6. The system of claim 1, wherein said first collimator can be adjusted.
7. The system of claim 1, wherein said extension Qx of said X-ray source in said x direction is between 2 and 50 times larger than said region of acceptance of said first graded multi-layer mirror in said x direction.
8. The system of claim 1, wherein said extension Qx of said X-ray source in said x direction is between 5 and 20 times larger than said region of acceptance of said first graded multi-layer mirror in said x direction.
9. The system of claim 1, wherein said extension Qy of said X-ray source in said x direction is 10 times larger than said region of acceptance of said first graded multi-layer mirror in said x direction.
10. The system of claim 2, wherein said extension Qy of said X-ray source (Q) in said y direction is between 2 and 50 times larger than said region of acceptance of said second graded multi-layer mirror in said y direction.
11. The system of claim 2, wherein said extension Qy of said X-ray source (Q) in said y direction is between 5 and 20 times larger than said region of acceptance of said second graded multi-layer mirror in said y direction.
12. The system of claim 2, wherein said extension Qy of said X-ray source (Q) in said y direction is 10 times larger than said region of acceptance of said second graded multi-layer mirror in said y direction.
13. The system of claim 1, wherein said region of acceptance of said first graded multi-layer mirror in said x direction is between 10 and 100 m.
14. The system of claim 2, wherein said region of acceptance of said second graded multi-layer mirror in said y direction is between 10 and 100 m.
15. The system of claim 1, wherein said first graded multi-layer mirror (A,B) is curved in one of a parabolic and elliptic shape.
16. The system of claim 2, wherein said second graded multi-layer mirror (A,B) is curved in one of a parabolic and elliptic shape.
17. The system of claim 1, wherein said first graded multi-layer mirror is flat.
18. The system of claim 2, wherein said second graded multi-layer mirror is flat.
19. An X-ray spectrometer with the X-ray optical system of claim 1.
20. An X-ray diffractometer with the X-ray optical system of claim 1.
21. An X-ray microscope with the X-ray optical system of claim 1.