Image Number 2 for United States Patent #4475280.
An integrated circuit incorporating high voltage semiconductor devices which are controlled by low voltage semiconductor devices is disclosed, including a method for making the same. The low voltage devices which are capable of realizing complex logic functions on the same chip are realized with only one simple extra step in the fabrication process as compared with the process used to fabricate discrete high voltage power transistors. The process addition to implant the low voltage device does not significantly degrade the original capability associated with discrete power transistors. Both laterally developed and vertically developed devices are described. The integrated circuit combines I.sup.2 L logic with power Darlington transistors. A large area ion implantation permits one to fabricate both low and high voltage devices on one substrate. The resulting integrated circuit permits a plurality of loads to be controlled by a simple or complex control function.