| 摘要 |
PURPOSE:To obtain an epitaxial wafer using a P<+> type silicon wafer having a high quality without misfitting dislocation and lower resistivity than a conventional allowable reference by satisfying the special relation between the resistivity of the wafer and the thickness of an epitaxial silicon film formed on the wafer. CONSTITUTION:An epitaxial silicon film having hundreds or more times of resistivity as large as that of a low resistance P<+> type silicon wafer in which boron is added as an impurity is formed on the wafer in such a manner that the resistivity rho of the wafer and the thickness (h) of the film formed on the wafer satisfy the relation of h <0.57rho<1.38> (where 1<=rho<=30; h:rhom unit, rho:10<-3>OMEGAcm unit). Thus, the epitaxial wafer using the P<+> type silicon wafer of lower resistivity than a conventional allowable reference with high quality without misfitting dislocation can be introduced. For example, in a megabit class memory circuit cell of MOS structure, storage holding time can be lengthened by approx. 50% as compared with the conventional one.
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