| 摘要 |
PURPOSE:To increase the working speed of an I<2>L (an integrated injection logic circuit) even at large currents without lowering the breakdown strength of a normal NPN transistor by forming structure in which a second epitaxial layer in low concentration is laminated onto a first epitaxial layer in high concentration. CONSTITUTION:Two-layer epitaxial-layer structure in which a first layer is formed by a first epitaxial layer 30 in high concentration and a second layer by a second epitaxial layer 300 in low concentration is shaped. When one conductivity type is represented by a P-type and the other conductivity type by an N-type, a P-type first base region 6a (a fifth region) as all internal base region in an I<2>L section A is formed so as to reach the first epitaxial layer 30 in high concentration. On the other hand, a P<+>-type base region 7c (a first region) is shaped so as to be stopped in the second epitaxial layer 300 in low concentration in a normal NPN transistor section B. Accordingly, working speed at large currents and low currents of the I<2>L can be increased without lowering the breakdown strength of the normal NPN transistor. |
