PSA-a new approach for bipolar LSI

Describes a new fabrication method to realize bipolar LSI. The new process, called the PSA (polysilicon self-aligned) method, is based on a new fabrication concept for dimensional reduction. The process provides smaller PSA transistors with smaller parasitic capacitance by being combined with local oxidation technology. As a production example of this modified PSA method, a static bipolar 4K TTL RAM has been manufactured. In this production, the nonepitaxial technology (triple diffusion) has also been adopted to shorten production turnaround time and to increase fabrication yield. Furthermore, PSA transistors have been combined with polysilicon diodes (PSD) and Schottky barrier diodes (SBD) to obtain low power Schottky diode-transistor logic (DTL) gates.