Comparison of Self-Aligned Silicide Technologies for Shallow CoSi2-Contacts in VLSI-Devices

For the formation of shallow, self aligned CoSi2-contacts we investigated different deposition techniques. Contacts were processed by using conventional silicide formation on preformed shallow junctions, the implantation through metal technique (ITM) and the dopant diffusion from silicide technique (DDS). Beside these techniques, where Co-films were deposited under HV-conditions by e-beam evaporation, the formation of CoSi2 on Si(100) substrates under UHV-conditions was investigated in order to eliminate the influence of impurities and especially the native oxide on the growth conditions. The specific contact resistances were determined with CBKR structures and the pn-junctions were characterized. Junction depths of 100 nm and 120 nm were reached for arsenic and boron doped contacts with the ITM-technique. Contacts processed under UHV-conditions show 4-5 times lower resistivities than conventional HV-contacts.