Abstract: A method deposits an epitaxial layer on a front side of a semiconductor wafer having monocrystalline material. The method includes: providing the semiconductor wafer; arranging the semiconductor wafer on a susceptor; heating the semiconductor wafer to a deposition temperature using thermal radiation directed to the front side and to the rear side of the semiconductor wafer; conducting a deposition gas over the front side of the semiconductor wafer; and selectively reducing an intensity of a portion of the thermal radiation that is directed to the rear side of the semiconductor wafer, as a result of which first partial regions at an edge of the semiconductor wafer, in the first partial regions a growth rate of the epitaxial layer is greater than in adjacent second partial regions given uniform temperature of the semiconductor wafer owing to an orientation of the monocrystalline material, are heated more weakly.

Abstract: Variations in wafer thickness due to non-uniform CVD depositions at angular positions corresponding to crystallographic orientation of the wafer are reduced by providing a ring below the susceptor having inward projections at azimuthal positions which reduce radiant heat impinging upon the wafer at positions of increased deposition.

Abstract: Optimized distribute database access techniques are disclosed. In various embodiments, a database request is received via a communication interface. The request is serviced using a corresponding one of a plurality of partial data set instances, each partial data set instance including a corresponding subset of data from a set of origin data, the partial data set instance used to service the request having an attribute, different from a corresponding attribute of one or more other of the plurality of partial data set instances, the attribute being associated with optimal servicing of the request by the partial data set instance used to service the request relative to said one or more other of the plurality of partial data set instances.

Abstract: Query-based routing of database requests is disclosed. In various embodiments, a database request is received via a communication interface. The request is parsed to extract one or more data elements associated with the request. Based at least in part on the one or more data elements extracted from the request, a selected one of a plurality of partial data set instances is selected, each partial data set instance including a corresponding subset of data from a set of origin data. The request is routed to the selected partial data set instance.

Abstract: A technique for query optimization includes determining that a query is associated with the query object, obtaining persistently-stored query response information associated with the query object, and using the persistently-stored query response information to generate a response to the query. The query optimization can be continuously performed.

Abstract: In various embodiments, a process for dynamic endpoint generation includes using a stored endpoint definition expressed in a declarative language to dynamically generate an endpoint comprising a representational state transfer (REST) interface. The process includes providing access to a locally-stored database via the endpoint and REST interface.

Abstract: In an embodiment, a process for providing optimized data access includes receiving at least a subset of data included in a set of origin data. The process includes transforming at least a portion of the subset of data in a manner associated with providing access to at least said portion of the subset of data in a manner that is optimized with respect to one or more parameters.

Abstract: In an embodiment, a process to provide data access optimized across access nodes includes receiving a subset of data included in a set of origin data, at least a portion of the subset of data being optimized for access from a respective data access node. The process further includes provide locally-optimized access to the subset of data.

Abstract: In an embodiment, a process for providing dynamically updated data access optimization includes receiving a subset of data included in a set of origin data and performing optimization to provide optimized access to the data via one or more data access nodes. The optimization includes applying a first transformation to at least a portion of the subset of data to provide a first optimized data, and providing the first optimized data to one or more of the one or more data access nodes. The optimization further includes subsequently determining to apply a second optimization comprising a second transformation to at least a portion of the subset of data to provide a second optimized data, and providing the second optimized data to one or more of the one or more data access nodes.

Abstract: A method deposits an epitaxial layer on a front side of a semiconductor wafer having monocrystalline material. The method includes: providing the semiconductor wafer; arranging the semiconductor wafer on a susceptor; heating the semiconductor wafer to a deposition temperature using thermal radiation directed to the front side and to the rear side of the semiconductor wafer; conducting a deposition gas over the front side of the semiconductor wafer; and selectively reducing an intensity of a portion of the thermal radiation that is directed to the rear side of the semiconductor wafer, as a result of which first partial regions at an edge of the semiconductor wafer, in the first partial regions a growth rate of the epitaxial layer is greater than in adjacent second partial regions given uniform temperature of the semiconductor wafer owing to an orientation of the monocrystalline material, are heated more weakly.

Abstract: A method for the sublimation growth of an SiC single crystal, involving heating up under growth pressure, is described. In the method for the sublimation growth of the SiC single crystal, a crucible holding a stock of solid SiC and an SiC seed crystal, onto which the SiC single crystal grows, is evacuated during a starting phase which precedes the actual growth phase and is then filled with an inert gas, until a growth pressure is reached in the crucible. Moreover, the crucible is initially heated to an intermediate temperature and then, in a heat-up phase, is heated to a growth temperature at a heat-up rate of at most 20° C./min. As a result, controlled seeding on the SiC seed crystal is achieved even during the heat-up phase.

Abstract: A device for the sublimation growth of an SiC single crystal, with foil-lined crucible. The device for producing an SiC single crystal includes a crucible with a crucible inner zone. Inside this zone, there is a storage area for storing a stock of solid SiC and a crystal area in which an SiC single crystal grows onto an SiC seed crystal. A heater device is arranged outside the crucible. On a side that faces the crucible inner zone, the crucible is lined with a foil of tantalum, tungsten, niobium, molybdenum, rhenium, iridium, ruthenium, hafnium or zirconium. As a result, the crucible is sealed and a reaction between the aggressive components of the SiC gas phase and the crucible wall is prevented.

Abstract: A seed crystal holder holds a SiC seed crystal while a SiC bulk single crystal is grown on the front surface of the seed crystal. The holder includes a back surface body with a bearing surface for bearing against a back surface of the SiC seed crystal. The holder includes a lateral mount for receiving the back surface body and the SiC seed crystal. The lateral mount has a projection located on an end facing the SiC seed crystal. The SiC seed crystal rests on the projection.

Abstract: An &agr;-SiC bulk single crystal is formed from an SiC gas phase by deposition of SiC on an SiC seed crystal. To enable an SiC bulk single crystal of the 15R type to be grown reproducibly and without restricting the seed crystal, the deposition takes place under a uniaxial tensile strength which includes a predetermined angle with the [0001] axis of the bulk single crystal, so that a rhombohedral crystal is formed.

Abstract: A method is described for growing at least one silicon carbide (SiC) single crystal by sublimation of a SiC source material. Silicon, carbon and a SiC seed crystal are introduced into a growing chamber. Then, the SiC source material is produced from the silicon and the carbon in a synthesis step that takes place before the actual growing. The growing of the SiC single crystal is then carried out immediately after the synthesis step. The carbon used is a C powder with a mean grain diameter of greater than 10 &mgr;m.

Abstract: A device for the sublimation growth of an SiC single crystal, with foil-lined crucible. The device for producing an SiC single crystal includes a crucible with a crucible inner zone. Inside this zone, there is a storage area for storing a stock of solid SiC and a crystal area in which an SiC single crystal grows onto an SiC seed crystal. A heater device is arranged outside the crucible. On a side that faces the crucible inner zone, the crucible is lined with a foil of tantalum, tungsten, niobium, molybdenum, rhenium, iridium, ruthenium, hafnium or zirconium. As a result, the crucible is sealed and a reaction between the aggressive components of the SiC gas phase and the crucible wall is prevented.

Abstract: A seed crystal holder holds a SiC seed crystal while a SiC bulk single crystal is grown on the front surface of the seed crystal. The holder includes a back surface body with a bearing surface for bearing against a back surface of the SiC seed crystal. The holder includes a lateral mount for receiving the back surface body and the SiC seed crystal. The lateral mount has a projection located on an end facing the SiC seed crystal. The SiC seed crystal rests on the projection.

Abstract: A method for the sublimation growth of an SiC single crystal, involving heating up under growth pressure, is described. In the method for the sublimation growth of the SiC single crystal, a crucible holding a stock of solid SiC and an SiC seed crystal, onto which the SiC single crystal grows, is evacuated during a starting phase which precedes the actual growth phase and is then filled with an inert gas, until a growth pressure is reached in the crucible. Moreover, the crucible is initially heated to an intermediate temperature and then, in a heat-up phase, is heated to a growth temperature at a heat-up rate of at most 20° C./min. As a result, controlled seeding on the SiC seed crystal is achieved even during the heat-up phase.

Abstract: An &agr;-SiC bulk single crystal is formed from an SiC gas phase by deposition of SiC on an SiC seed crystal. To enable an SiC bulk single crystal of the 15R type to be grown reproducibly and without restricting the seed crystal, the deposition takes place under a uniaxial tensile strength which includes a predetermined angle with the [0001] axis of the bulk single crystal, so that a rhombohedral crystal is formed.

Abstract: A device for producing a silicon carbide (SiC) single crystal contains a crucible having a storage region for holding a stock of solid SiC and having a crystal region for holding a SiC seed crystal. An insert made from glassy carbon is disposed in the crucible. In the method, solid SiC is sublimed as a result of the stock being heated and SiC in the gas phase is generated, which is conveyed to the SiC seed crystal, on which it grows as an SiC single crystal. A heat flux is controlled by an insert made from glassy carbon.