Effects of Phosphorus Diffusions in Epitaxial Silicon Layers

The diffusion of phosphorus into epitaxial silicon has been investigated by evaluating the electrical and structural characteristics of the epitaxial diffused guard-r ing junctions. The effects of stacking faults in epitaxial silicon on the junction characteristics were found to depend on the surface condition of the epitaxial layer before diffusion. Localized breakdown, as evidenced by light emission, was observed at the stacking fault grooves only when the epitaxial layer was etched before diffusion. Stacking faults were also found to be trans-formed into other defects after diffusion; chemical etching of the epitaxial layer also had a great influence on this transformation. Dislocations were observed in the phosphorus-diffused r gions. The dislocations occur in hexagonal net= works parallel to the diffusion front and come to the surface at the intersection of the junction and the surface in planar devices. Guarded junctions formed by these phosphorus diffusions exhibit localized breakdown with microplasma phenomena. The dislocation density was determined and correlated reasonabl