A High-Density Bipolar Logic Masterslice for Small Systems

A new high-density bipolar logic masterslice which uses a simple Schottky Transistor Logic (STL) circuit cell as its basic building block is presented in this paper. The STL cell is derived from Integrated Injection Logic (I
²
L). The use of low-barrier Schottky diodes for AND logic, as diodes function in Diode Transistor Logic (DTL), makes possible achieving the NAND circuit operation. A brief description of the Schottky diode fabrication process is also given. A new concept of contact hole personalization is introduced and is shown to be an efficient approach to masterslice design as well as a factor in achieving high cell density. Due to the unusual structure of the basic cell and the arrangement of the cells in the masterslice, a new physical design methodology was developed for the design of different part numbers, corresponding to unique logic functions, on this masterslice. The STL circuit operates with a 1.7-V power supply and yields a typical delay of 3 ns at 0.5 mW and 5 ns at 0.15 mW. The I/O circuits are TTL-level compatible. The cells, the circuits, the unique features of the masterslice, and its application in an I/O controller chip are described.