Highly conductive shallow junction formation

Abstract

The invention relates to a method of forming a shallow junction. The method () comprises forming source/drain extension regions with a non-amorphizing tail implant () which is annealed conventionally (spike/RTP) and amorphizing implant which is re-grown epitaxially (SPER) (). The non-amorphizing tail implant is generally annealed () before a doped amorphous layer for SPE is formed (). SPE provides a high active dopant concentration in a shallow layer. The non-amorphizing tail implant () expands the source/drain extension region beyond the range dictated by the SPE-formed layer and keeps the depletion region of the P-N junction away from where end-of-range defects form during the SPE process. Thus, the SPE-formed layer primarily determines the conductivity of the junction while the tail implant determines the location of the depletion region. End-of-range defects form, but are not in a position to cause significant reverse bias leakage.