METHOD OF FABRICATING IMPURITY AREA SUPERIMPOSED WITH BORON AND DOPED BORON

摘要

A process for fabricating devices having overlapping heavily doped impurity regions of opposite conductivity wherein the formation of crystallographic faults emanating from the overlapping regions is eliminated. It has been discovered that crystallographic faults can be avoided by limiting the total N and P impurity concentrations in the overlapped regions. The process includes forming in the semiconductor substrate a first arsenic doped region having a maximum impurity concentration in the range of 5x1020 to 3x1021 atoms/cc, and forming in the silicon substrate a second adjacent boron doped region in partial overlapping relation to the first region having a maximum impurity concentration in the range of 5x1019 to 3x1020 atoms/cc.