The influence of Ti capping layers on CoSi2 formation

Cobalt silicide formation is very sensitive to the presence of oxygen. Oxygen contamination may originate from different sources: impurities in the annealing ambient, oxygen incorporated within the deposited Co layer and interfacial oxide at the Co/Si interface. In this work, it is shown that the cause of the sensitivity towards oxygen contamination is the formation of a SiOx diffusion barrier between CoSi and the unreacted Co. This causes an increase in the activation energy for CoSi formation. Furthermore, we will show that a titanium capping layer eliminates the sensitivity of CoSi2 formation for oxygen contamination, thus improving the formation of CoSi2 layers. (C) 2000 Elsevier Science B.V. All rights reserved.