Patent ID: 8372298

Claim:
A method for producing epitaxially coated silicon wafers, in which a multiplicity of silicon wafers which are polished at least on their front sides are provided and successively coated individually in an epitaxy reactor, comprising: placing a respective silicon wafer on a susceptor in the epitaxy reactor, and pretreating the wafer in a first step under a hydrogen atmosphere at a hydrogen flow rate of 1-100 slm; and increasing the global flatness of the wafer by pretreating the wafer in a second step with addition of an etching medium to the hydrogen atmosphere, at a hydrogen flow rate of 1-100 slm, and a flow rate of the etching medium of 0.5-1.5 slm, the pretreating taking place at an average temperature of 950-1050° C., wherein, during at least the second step of pretreating, the power of heating elements arranged above and below the susceptor is regulated such that there is a temperature difference of 5-30° C. between a radially symmetrical central region of the silicon wafer to be epitaxially coated, and an outer portion of the silicon wafer which lies outside the central region, and subsequently epitaxially coating the wafer on its polished front side and removing the wafer from the epitaxy reactor.