Fabrication process for schottky barrier diodes on a single poly bipolar

Abstract

A method for fabricating a diode, for example, for use in a Schottky clamped transistor, which as a process step disposes a layer of oxide between the substrate and the overlying layer of polysilicon which must ultimately be etched away. The oxide layer permits use of an end point dry etch process which in turn allows greater miniaturization of the circuit over wet etch processes. Use of the end point process made feasible by the oxide layer also prevents overetch of the silicon material. As a result, a more ideal metal silicide anode-to-substrate Schottky barrier is formed with corresponding improvements in the diode ideality factor. In addition the oxide layer eliminates Schottky mask alignment problems and further improves diode performance characteristics by elimination of parasitic diodes. The process can be implemented with minimal deviation from other core processes used to fabricate similar circuits.