Nature and mechanism of emitter-collector short in oxide isolated bipolar integrated circuits

Nature and mechanism of emitter-collector short of npn transistors in bipolar integrated circuits have been investigated for a device made by means of oxide isolation and arsenic emitter diffusion. The role of oxidation-induced dislocation, generated during the isolation process, plays predominant role on the emitter-collector short, because diffusion of arsenic tends to be anomalously deep along the oxidation-induced dislocation array. Conditions under which the generation of dislocations can be avoided are obtained for combinations of buffer oxide thickness and nitride thickness used as a mask for the isolation oxidation.