| 摘要 |
PURPOSE:To obtain an element of N<+> -N-P type structure increased in only the impurity density in the vicinity of the surface of a doner impurity diffused layer by diffusing the doner impurity having a segregation coefficient larger than 1 in an Si wafer and forming a thermal oxide film (SiO2) on the surface of the diffused layer. CONSTITUTION:Phosphorus (or antimony or arsenic) is diffused as a doner impurity in the upper surface of a P type Si substrate crystal 1 to form an N type layer 2, and a thermal oxide film 3 is formed on the upper surface of the layer 2, and an N<+> type layer 4 is formed by impurity redistribution effect in the vicinity of the upper surface of the layer 2. The redistribution of the impurity upon formation of the film 3 depends upon the segregation coefficient (m) of the impurity in the boundary between the thermal oxide film 3 and the Si. In case of m>>1 (P, Sb, As have m 10.), the impurity density in the vicinity of the upper surface of the layer 2 is increased as the thermal oxide film 3 is grown. |
