Semiconductor substrate and manufacturing method thereof

摘要

A semiconductor substrate of the present invention is a DSP wafer or Semi-DSP wafer (FIG. 2) having a flatness of an SFQR value <=70 (nm) and containing boron at a concentration not lower than 5x10<16 >(atoms/cm<3>) nor higher than 2x10<17 >(atoms/cm<3>) within 95% or more of rectangular regions of 25x8 (mm<2>) arranged on a front face of the substrate. Specifically, a silicon crystal layer by an epitaxial growth is formed on a front face of a silicon substrate having the above substrate boron concentration.