Highly Reliable Contacts to Silicon Enabled by Low Temperature Sputtered Graphenic Carbon

Titanium silicide (TiSi) contacts are frequently used metal-silicon contacts but are known to diffuse into the active region under high current density stress pulses. Recently, we demonstrated that graphenic carbon (GC) deposited by CVD at 1000∘C on silicon has the same low Schottky barrier as TiSi, but a much improved reliability against high current density stress pulses. In this paper we demonstrate now that the deposition of graphenic carbon is possible at 100∘C -400∘C by a sputter process. We show that the sputtered carbon-silicon (SC-Si) contact is over 1 billion times more stable against high current density pulses than the conventionally used TiSi-Si junction, while it has the same or even a lower Schottky barrier. SC can be doped by nitrogen (CN) and this results in an even lower resistivity and improved stability. Scalability of the CN thickness down to 5nm is demonstrated. The finding that there is a low temperature approach for using the excellent carbon properties has important consequences for the reliability of contacts to silicon and opens up the use of GC in a vast number of other applications.     «

Titanium silicide (TiSi) contacts are frequently used metal-silicon contacts but are known to diffuse into the active region under high current density stress pulses. Recently, we demonstrated that graphenic carbon (GC) deposited by CVD at 1000∘C on silicon has the same low Schottky barrier as TiSi, but a much improved reliability against high current density stress pulses. In this paper we demonstrate now that the deposition of graphenic carbon is possible at 100∘C -400∘C by a sputter process....     »