An investigation of single crystal Co-SALICIDE (self-aligned silicide) process for deep sub-micrometer CMOS devices

Abstract

In this paper, the Co-SALICIDE process has been investigated intensively for the application to deep sub-micron CMOS VLSI. Adopting a Co/Ti/Si structure, epitaxial growth of a single crystal CoSi/sub 2/ film on the [100] Si substrate through two-step RTA has been demonstrated in detail. The heat-reaction characteristics of the Co/Ti/Si structure for forming the single crystal CoSi/sub 2/ film have been studied. We have applied the single crystal CoSi/sub 2/ to SALICIDE process post junction fabrication to obtain a smoother interface. Focusing on the disadvantage of a large leakage current that Co-salicided diodes usually suffer, ultra-shallow junctions especially, we found the leakage current to be large and investigated several methods to reduce diode leakage. The experiments show that PAI can improve the inverse I-V characteristics remarkably. A leakage current density of a Co-salicided diode as low as 8/spl times/10/sup -8/ A/cm/sup 2/ (V=5 v) was obtained for a junction depth of 107 nm. The resistivity of the single crystal CoSi/sub 2/ film is 16.5 /spl mu//spl Omega//sub (BH)/cm.