PURPOSE: To improve the electrical characteristics of a semiconductor element by a method wherein the semiconductor element having junctions at the boundaries of respective impurity regions is formed and subjected to tungsten halogen lamp annealing.

CONSTITUTION: Boron ions and arsenic ions are implanted into a silicon substrate 1 to form a semiconductor element having junctions at the boundaries of respective impurity regions. The semiconductor element is subjected to a tungsten halogen lamp annealing. A base diffused region 3 formed by the implantation of boron is widened by annealing. On the other hand, an emitter diffused region 4 formed by the implantation of arsenic is hardly widened by annealing. Therefore, the width 5b of an intrinsic base region is widened. With this constitution, the electrical characteristics of the semiconductor element can be improved.