| 摘要 |
PURPOSE:To eliminate the dispersion of junction capacity by a method wherein impurities, conduction types thereof are the same as one conduction type semiconductor substrate but diffusion coefficients thereof differ, are simultaneously introduced to the substrate, a deep region with low surface concentration and a shallow region with high surface concentration are made up, and an opposite conduction type region is diffused to the regions. CONSTITUTION:SiO2 films 2 with windows 3 are built up on N<-> type Si substrates 1, a plurality of substrates 1 are erected on a quartz boat 5 at intervals, and an impurity source 4 of Si containing P and As, diffusion coefficients thereof differ, is erected at one end section of the boat 5. The boat is enclosed in a quartz capsule 6, and thermally treated at about 1,150 deg.C for 3hr, and deep P diffusion layers 7 with low concentration and shallow As diffusion layers 8 with high concentration located on the layers 7 are made up in the substrate 1 exposing in the windows 3. B impurities are diffused into the layer 8 again by means of a capsule diffusion method, and a P type layer 9 is built up. Thus, the dispersion of junction capacity and a coefficient of capacity variation is reduced, and the yield of production is improved. |
