Limitations in Microelectronics - II. Bipolar Technology

The physical phenomena which will ultimately limit miniaturization of planar bipolar integrated circuits are examined. The maximum packing density is obtained by minimizing the supply voltage and the size of the devices. The minimum transistor size is determined by junction breakdown, punch through and doping fluctuations. For circuits that are fully active the maximum number of circuit functions per chip is determined by power dissipation. The packing density of read-only memories becomes limited by the area occupied by devices and interconnections. The limitations of MOS and bipolar technologies are compared. It is concluded that read-only memories will reach approximately the same performance and packing density with MOS and bipolar technologies, while fully active circuits will reach the highest levels of integration with dynamic MOS or complementary MOS technologies