Integrated circuit with zener diode and transistor - has buried layers and diode region formed simultaneously with transistor collector

摘要

The integrated circuit has the semiconductor substrate of one type provided with two highly doped buried layers (2,3) of a second type via diffusion, one being used for a Zener diode and the other for a transistor. The substrate is provided with an epitaxial layer (4) of the same type as the buried layers (2,3) with separation zones (5) of opposite type extending through it as the surface of the substrate (1). Two zones (6,7) of the same type as the buried layers (2,3) are formed simultaneously to provide one diode region and the transistor collector respectively. Further zones comprising the second diode zone (8) and the transistor base zone (10) are then formed simultaneously before provision of the emitter zone (11) simultaneous with the formation of a diode connection zone (9). The Zener diode incorporated in the integrated circuit allows Zener voltages between 6.5 and 10 volts to be used.