Semiconductor device having an electrode which controls a surface state of the base area for minimizing a change of the D.C. amplification ratio

摘要

A bipolar transistor having a control electrode area of a semiconductor of a first conductive type, and first and second main electrode areas positioned in contact with the control electrode area and composed of a semiconductor of a second conductive type different from the first conductive type, comprises, for the purpose of preventing depletion of the surface of the control electrode area and suppressing or annulating the current generated in the surfacial depletion area, an electrode for controlling the surface state of the control electrode area, positioned, across an insulation film, on the surface of the control electrode area including the vicinity of the junction between the control electrode area and the above-mentioned first main electrode area.