Rapidly annealed Mo-Polycide For VLSI gates and interconnects

Abstract

In this paper, the results of an investigation on the formation of Mo-polycide by sputtering from a composite target followed by rapid thermal annealing (RTA) is presented. The influences of target stoichiometry and other deposition parameters including cathode power, Ar-pressure, dc bias and substrate temperature were investigated before and after an RTA cycle. The deposition at high substrate temperature resulted in high oxygen content and high film stress. On the other hand, dc bias and Ar pressure have been found to have insignificant effect on film properties. A final MoSi2 film resistivity of 72 μΩ cm was achieved by sputtering from a MoSi2.1 target at ambient temperature followed by RTA at 1100° C for 10 s. This RTA cycle was compatible with that required for implant activation and glass reflow. NMOS FETs having Mo-polycide gates were fabricated using RTA to simultaneously activate implanted dopants and to reflow PSG. Excellent I-V characteristics of these devices indicate that no damage to gate oxide was induced by using rapidly annealed Mo-polycide.