1. A method of fabricating a semiconductor photodetector, the method comprising the steps:
forming a semiconductor structure comprising a single-crystal semiconductor substrate; a second layer of an insulating material, and a third layer comprising essentially Si;
growing epitaxially a fourth layer of essentially Ge, the fourth layer having a surface layer;
annealing to reduce threading dislocation density;
forming isolation regions surrounding said third layer and said fourth layer, said isolation regions having a top border adjacent to or above said fourth layer and a bottom border adjacent to said second layer;
forming alternating stripes of p-type and n-type doped material adjacent to said surface layer such that regions of non-intentionally-doped material remain between said alternating stripes; and
forming a set of electrodes on said surface layer comprising a plurality of interdigitated members, wherein the entirety of the portion of said electrodes that is in contact with said surface layer also is in contact with said stripes of p-type and n-type doped material.
2. The method of claim 1, wherein said fourth layer has a thickness greater than 50 nm, and the combined thickness of said third layer and said fourth layer is less than 500 nm.
3. The method of claim 1, wherein the combined average Ge concentration of said third layer and said fourth layer is greater than 80%.
4. The method of claim 1, further comprising forming a Si seed layer before the growth of said fourth layer of Ge.
5. The method of claim 1, wherein said stripes of p-type and n-type doped material are formed by ion implantation and subsequent annealing.
6. The method of claim 1, further comprising the deposition a transparent dielectric material on top of the portions of said surface layer not in direct contact with said electrodes and having a refractive index between 1 and that of said fourth layer so as to act as an anti-reflection coating.
7. The method of claim 1, wherein the annealing is performed at a temperature in the range between 750\xb0 C. and 900\xb0 C.
8. The method of claim 1, wherein the annealing forms an additional layer of Si1-xGex between said third layer of Si and said fourth layer of Ge, as a result of interdiffusion.
9. The method of claim 1, wherein said third layer of Si and said fourth layer of Ge interdiffuse during the annealing to form a layer of Si1-xGex with a Ge concentration, x, that varies continuously from a minimum value adjacent to said second layer to a maximum value at said surface layer.
10. A method of fabricating a semiconductor photodetector, the method comprising the steps:
forming a semiconductor structure comprising a single-crystal semiconductor substrate; a second layer of an insulating material, and a third layer comprising essentially Si;
growing epitaxially a fourth layer of essentially Ge;
growing epitaxially a fifth layer of essentially Si1-zGez, the fifth layer having a surface layer;
annealing to reduce threading dislocation density;
forming isolation regions surrounding said third layer and said fourth layer and said fifth layer, said isolation regions having a top border adjacent to or above said fourth layer and a bottom border adjacent to said second layer;
forming alternating stripes of p-type and n-type doped material adjacent to said surface layer such that regions of non-intentionally-doped material remain between said alternating stripes; and
forming a set of electrodes on said surface layer comprising a plurality of interdigitated members, wherein the entirety of the portion of said electrodes that is in contact with said surface layer also is in contact with said n-type or said p-type doped material.
11. The method of claim 10, wherein said fifth layer of essentially Si1-zGez, is grown after the annealing, but before the forming of the isolation regions.
12. The method of claim 10, wherein said fifth layer of essentially Si1-zGez, is grown after step forming of the isolation regions, but before forming the alternating stripes of p-type and n-type doped material.
13. A method of fabricating a semiconductor photodetector, the method comprising the following steps:
forming a semiconductor structure comprising a single-crystal semiconductor;
growing epitaxially a second layer of a crystalline insulating material;
growing epitaxially a third layer of essentially Ge, the third layer having a surface layer;
annealing to reduce threading dislocation density;
forming isolation regions surrounding said third layer, said isolation regions having a top border adjacent to or above said third layer and a bottom border adjacent to said second layer;
forming alternating stripes of p-type and n-type doped material adjacent to said surface layer such that regions of non-intentionally-doped material remain between said alternating stripes; and
forming a set of electrodes on said surface layer comprising a plurality of interdigitated members, wherein the entirety of the portion of said electrodes that is in contact with said surface layer also is in contact with said n-type or said p-type doped material.
14. The method of claim 13, wherein said second layer comprises (Ba,Sr)O, BaTiO3, SrTiO3, SrRuO3, MgO, TiO2, or combinations thereof.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A system for caching information, comprising:
a multidimensional objects interface that allows for accessing at least one multidimensional object providing dynamic multidimensional analysis data derived from a database;
a cache interface that allows for accessing and controlling at least one cache providing dynamic multidimensional analysis data derived from the multidimensional object; and
at least one analysis component coupled to the multidimensional object and the cache for proactively controlling access to the multidimensional object and the cache.
2. The system of claim 1, the database comprising a relational database.
3. The system of claim 1, the multidimensional object comprising a ROLAP object.
4. The system of claim 1, the cache comprising a MOLAP cache.
5. The system of claim 1, the multidimensional object comprising real-time access analysis data and the cache comprising quick access analysis data.
6. The system of claim 1, the analysis component, comprising a Unified Dimensional Model (UDM).
7. The system of claim 1, the analysis component, comprising:
at least one input for determining when to proactively control the cache; and
a query interpreter for receiving and qualifying queries based upon the input.
8. The system of claim 7, the input comprising at least one selected from the group consisting of a user input and a system input for proactively controlling the cache.
9. The system of claim 8, the system input comprising a database update notification.
10. The system of claim 8, the user input comprising at least one selected from the group consisting of a quiet time delay, a quiet time delay override, a forced refresh time, and a user initiated partial cache rebuild.
11. The system of claim 8, the system input comprising at least one selected from the group consisting of a last database update tracker, tables affecting OLAP objects, and a dependent OLAP objects data source tracker.
12. The system of claim 1, the analysis component having proactive caching operational modes comprising at least one selected from the group consisting of a ROLAP mode, a MOLAP mode, and a MOLAPROLAP mode.
13. The system of claim 12, the ROLAP mode operatively triggered by at least one selected from the group consisting of quiet time delay met, quiet time delay override met, forced refresh time met, and database updated.
14. The system of claim 12, the MOLAP mode operatively triggered by at least one selected from the group consisting of:
equivalent query data available from both a MOLAP cache and a ROLAP object; and
a user demand.
15. The system of claim 12, the MOLAPROLAP mode operatively triggered by at least one selected from the group consisting of both real-time and low latency queries required and partial rebuilding of a MOLAP cache required.
16. The system of claim 1, the analysis component having capabilities to process multiple queries each requiring different proactive cache handling.
17. The system of claim 1, the analysis component having capabilities to process a parsed query, each part requiring different proactive cache handling.
18. The system of claim 1, the analysis component comprising an adaptive tuning component for optimizing the analysis component.
19. The system of claim 18, the adaptive tuning component, comprising:
a query interpreter for handling queries and instigating query sessions with the multidimensional object and the cache;
a result comparator operatively connected to the query interpreter for determining differences between the query sessions of the multidimensional object and the cache; and
a performance optimizer operatively connected to the result comparator for optimizing the query interpreter based on the differences determined by the result comparator.
20. A method of database serving, comprising:
coupling operatively to at least one multidimensional object derived from at least one database and to at least one cache comprising dynamic multidimensional analysis data derived from the multidimensional objects; and
controlling proactively access to the multidimensional object and the cache in response to a query.
21. The method of claim 20, the multidimensional object comprising a ROLAP object.
22. The method of claim 20, the database comprising a relational database.
23. The method of claim 20, the cache comprising a MOLAP cache.
24. The method of claim 20, further comprising:
processing the multidimensional objects to produce the cache.
25. The method of claim 24, the processing comprising a background transaction.
26. The method of claim 24, further comprising:
monitoring the database for relevant changes; and
reprocessing the multidimensional objects to produce an updated cache when relevant changes occur.
27. The method of claim 24, further comprising:
canceling the processing of the multidimensional objects when at least one selected from the group consisting of an automatic condition detected and a user initiated action detected occurs.
28. The method of claim 27, the automatic condition detected comprising a database change.
29. The method of claim 27, the user initiated action detected comprising at least one selected from the group consisting of committing processing of a multidimensional object and starting another transaction on a multidimensional object.
30. A system for caching information, comprising:
first means for providing dynamic multidimensional analysis data derived from a database;
second means for providing dynamic multidimensional analysis data derived from the first means; and
third means for coupling the first means and the second means for proactively controlling access to the first and second means to provide a desired query response regarding the database.
31. A method of caching data, comprising:
providing at least one multidimensional object providing dynamic multidimensional analysis data derived from a database;
constructing at least one cache providing dynamic multidimensional analysis data derived from at least one multidimensional object;
switching an operational mode of an analysis component to access the cache only for query analysis; and
analyzing queries utilizing the cache.
32. The method of claim 31, further comprising:
determining if any changes to relevant multidimensional objects have occurred; and
switching the analysis component operational mode to access the multidimensional objects when relevant changes have occurred.
33. The method of claim 32, further comprising:
removing all cache related to the relevant changes; and
rebuilding the cache based on changed multidimensional objects.
34. The method of claim 31, further comprising:
determining if a query requires at least one selected from the group of low latency data and real-time data.
35. The method of claim 34, further comprising:
switching the analysis component to a MOLAPROLAP operational mode when both low latency and real-time data are required.
36. The method of claim 31, the multidimensional objects comprising ROLAP objects.
37. The method of claim 31, the database comprising a relational database.
38. The method of claim 31, the cache comprising a MOLAP cache.
39. The method of claim 31, the analysis component comprising a UDM.
40. The method of claim 31, the analysis component having operational modes comprising at least one selected from the group consisting of a MOLAP mode, a ROLAP mode, and a MOLAPROLAP mode.
41. A method of proactive caching, comprising:
providing an input related to determining an operational mode;
determining the operational mode based, at least in part, upon the input;
providing at least one multidimensional object providing dynamic multidimensional analysis data derived from a database;
building at least one cache providing dynamic multidimensional analysis data derived from at least one multidimensional object;
switching an analysis component having operational modes to the determined operational mode; and
processing queries via the analysis component utilizing the determined operational mode.
42. The method of claim 41, further comprising:
determining if any changes to relevant multidimensional objects have occurred; and
switching the analysis component operational mode to access the multidimensional objects when relevant changes have occurred.
43. The method of claim 42, further comprising:
removing all cache related to the relevant changes; and
rebuilding the cache based on the changed multidimensional objects.
44. The method of claim 41, further comprising:
determining relevant changes during the building of the cache; and
canceling the building of the cache when relevant changes occur.
45. The method of claim 41, the input comprising at least one selected from the group consisting of at least one user input and at least one system input.
46. The method of claim 45, the user input comprising at least one selected from the group consisting of a low latency query request and a real-time query request.
47. A method of proactive caching, comprising:
providing at least one multidimensional object providing dynamic multidimensional analysis data derived from a database;
building at least one cache providing dynamic multidimensional analysis data derived from at least one multidimensional object;
providing an input for designating data;
determining if any changes to relevant multidimensional objects have occurred;
switching the analysis component operational mode to access the multidimensional objects when relevant changes have occurred; and
rebuilding the cache based on the changed relevant multidimensional objects.
48. The method of claim 47, the input comprising data desired to be updated.
49. The method of claim 48, changes to relevant multidimensional objects including the data desired to be updated.
50. The method of claim 47, the input comprising information for linking data to relevant multidimensional objects.
51. The method of claim 50, further comprising:
switching the analysis component to an operational mode to access the cache only after rebuilding the cache; and
processing queries via the analysis component utilizing the cache.
52. A method of proactive caching, comprising:
providing at least one multidimensional object providing dynamic multidimensional analysis data derived from a database;
building at least one cache providing dynamic multidimensional analysis data derived from at least one multidimensional object;
providing an input for determining a cache rebuild parameter;
determining if the cache rebuild parameter has been satisfied;
switching the analysis component operational mode to access the multidimensional objects when the cache rebuild parameter has been satisfied; and
rebuilding the cache based on relevant multidimensional objects.
53. A method of claim 52, the cache rebuild parameter comprising at least one selected from the group consisting of a forced refresh rate, a quiet time delay, and a quiet time delay override.
54. A method of optimizing proactive caching, comprising:
inputting a query into a query interpreter;
loading the query into at least two sessions, each session accessing different database derived data sources;
comparing resulting data from the sessions to determine differences via a result comparator; and
analyzing the differences of the sessions to adaptively optimize the proactive caching by the query interpreter.
55. A data packet transmitted between two or more computer components that facilitates data analysis, the data packet comprising dynamic multidimensional analysis data, based, in part, on a proactive caching structure.
56. The data packet of claim 55, the dynamic multidimensional analysis data comprising at least one selected from the group consisting of a multidimensional object data derived from a database and a dynamic multidimensional analysis data derived from at least one multidimensional object.
57. The data packet of claim 56, the dynamic multidimensional analysis data derived from at least one multidimensional object comprising data from a MOLAP cache.
58. The data packet of claim 56, the multidimensional object data comprising data from an OLAP object.
59. The data packet of claim 58, the OLAP object comprising a ROLAP object.
60. The data packet of claim 56, the database comprising a relational database.
61. A computer readable medium storing computer executable components of a system for facilitating data analysis, comprising a proactive caching system that provides information associated with a data set, based, at least in part, upon at least one OLAP variant cache.
62. The medium of claim 61, the OLAP variant cache comprising MOLAP cache.
63. The medium of claim 61, the proactive caching system comprising:
at least one analysis component capable of being proactively coupled to a multidimensional object and to a cache comprising dynamic multidimensional analysis data derived from the multidimensional object, proactively controlling access to the multidimensional object and the cache.
64. A device employing the system of claim 1 comprising at least one from a group consisting of a computer, a server, and a handheld electronic device.