Abstract: This work studied the technology of formation of pn junction and self-aligned CoSi₂ film contact on Si doped with B P As by diffusion or ion implantaion. Ion beam sputtering was applied for Co film deposition, and solid state interaction of Co/Si was performed by rapid thermal process (RTF) to form CoSi₂ films. The sheet resistances of doped Si regions decreased by an order of magnitude after CoSi₂ formation. For the samples implanted with As, the effects of different thermal processes on As redistribution during interaction of Oo/Si were investigated. Experimental results indicated that in the case of conventional process (As was activated prior to CoSi₂ formation), a snowplow effect of As during interaction of Co/Si was observed. In the case of concurrent process (As activation and interaction of Co/Si were carried out in one step), As exibited an obviously different behavior. The spreading resistance probe and electrical characterization showed that, for either of the above two cases, a high.carrier concentration can be produced at the interface of CoSi₂/Si, and the pn junctions with CoSi₂ contact exibited good I-V properties, and their leakage current was much less than that of the comparative pn. junction with Al/Si contact.

Key words: As implantation, solid state interaction, CoSi₂ film, pn junction