| Patent application number | Description | Published |
|---|
| 20100176491 | Epitaxially Coated Silicon Wafer and Method For Producing Epitaxially Coated Silicon Wafers - Silicon wafers polished on their front sides are individually placed on a susceptor in an epitaxy reactor and firstly pretreated under a hydrogen atmosphere, and secondly with addition of an etching medium with a flow rate of 1.5-5 slm to the hydrogen atmosphere, the hydrogen flow rate being 1-100 slm in both steps, and subsequently epitaxially coated on the polished front side, and then removed from the reactor. In a second method, gas flows introduced into the reactor by injectors are distributed into outer and inner zones of the chamber, such that the inner zone gas flow acts on a wafer central region and the outer zone gas flow acts on a wafer edge region, the inner/outer distribution of the etching medium I/O=0-0.75. Silicon wafers having an epitaxial layer having global flatness value GBIR of 0.02-0.06 μm, relative to an edge exclusion of 2 mm are produced. | 07-15-2010 |
| 20100213168 | Method For Producing Epitaxially Coated Silicon Wafers - Epitaxially coated silicon wafers, are coated individually in an epitaxy reactor by a procedure in which a silicon wafer on a susceptor in the epitaxy reactor, is pretreated in a first step with a hydrogen flow rate of 1-100 slm and in a second step with hydrogen and an etching medium at a hydrogen flow rate of 1-100 slm, and an etching medium flow rate of 0.5-1.5 slm, at an average temperature of 950-1050° C., and is subsequently coated epitaxially, wherein, during the second pretreatment step, the power of heating elements is regulated such that there is a temperature difference of 5-30° C. between a radially symmetrical central region of the silicon wafer and an outer region of the silicon outside the central region. | 08-26-2010 |
| 20100294197 | Methods For Producing Epitaxially Coated Silicon Wafers - Epitaxially coated silicon wafers are produced by placing a wafer polished on its front side on a susceptor in an epitaxy reactor, first pretreating under a hydrogen atmosphere and in a second and a third step with addition of an etching medium to the hydrogen atmosphere, and subsequently providing an epitaxial layer, wherein during the first and second steps the hydrogen flow rate is 20-100 slm, during the second and third steps the flow rate of the etching medium is 0.5-1.5 slm, during the second step the average temperature in the reactor chamber is 950-1050° C., and the power of heating elements above and below the susceptor is regulated such that there is a temperature difference of 5-30° C. between a radially symmetrical region encompassing the central axis of and a part lying outside this region; and during the third step the hydrogen flow rate is reduced to 0.5-10 slm. In a second method, during the third pretreatment step the flow rate of the etching medium is increased to 1.5-5 slm, while the hydrogen flow rate does not have to be reduced. | 11-25-2010 |
