PURPOSE: To reduce the dispersion of current amplification factors by a method wherein a phospho-silicate glass film is formed at the other step than the forming step for an emitter region.

CONSTITUTION: A Si oxide film 2b and a p type base region 4 are formed on an n type Si substrate 1. Next, an n type emitter region 5 and the phospho-silicate glass film 10 are formed. Then, current amplification factor is measured by opening windows 7 and 8 and then making a metallic needle abut against the regions 5 and 4. If the current amplification factor is out of a fixed range, redistribution diffusion heat treatment of the impurity in the region 5 is performed. For good products of the factor within the fixed range, an emitter and base electrodes are formed through the windows 7 and 8.