Reduced Al/PtSi reaction up to 600°C using an amorphous carbon barrier layer

Abstract

An amorphous carbon barrier layer is used to reduce the reaction between PtSi and Al for interconnect application. Using a carbon layer of 1000 Å and a structure of Al/C/PtSi (2000 Å/1000 Å/850 Å/Si substrate), the preformed PtSi is shown to remain stable after a 30-min anneal at 600°C in a N2-H2 ambient, with no PtAl2, the reaction product between Al and PtSi, detected. The Al-PtSi reaction is nearly completed after an anneal of 30 min at 650°C. Sheet resistance measurement confirms the low resistance of the top Al layer at these temperatures. The much reduced reaction between Al and PtSi using an amorphous carbon barrier layer, with similar results on the Al/Pd2Si reaction, makes carbon a promising barrier between Al and silicide contacts.