Silicon wafer and process for producing it

摘要

A process for producing a single-crystal silicon wafer, comprises the following steps: producing a layer on the front surface of the silicon wafer by epitaxial deposition or production of a layer whose electrical resistance differs from the electrical resistance of the remainder of the silicon wafer on the front surface of the silicon wafer, or production of an external getter layer on the back surface of the silicon wafer, and heat treating the silicon wafer at a temperature which is selected to be such that an inequality (1) 1 $\left[Oi\right]<{\left[Oi\right]}^{\mathrm{eq}}\left(T\right)\exp \frac{2{\mathrm{sigma}}_{\mathrm{SiO}2}\mathrm{Omega}}{rkT}$ is satisfied, where [Oi] is an oxygen concentration in the silicon wafer, [Oi](T) is a limit solubility of oxygen in silicon at a temperature T, sigmaSiO2 is the surface energy of silicon dioxide, Omega is a volume of a precipitated oxygen atom, r is a mean COP radius and k the Boltzmann constant, with the silicon wafer, during the heat treatment, at least part of the time being exposed to an oxygen-containing atmosphere.