Flicker noise characterization of Co-silicide/SiGe contacts using TLM test structures

The flicker noise characterization of Co-silicide/p/sup +/-SiGe contacts with different Si/SiGe epitaxial structures have been performed to evaluate the interface quality of contacts. Si/SiGe layers prepared by ultra-high vacuum chemical molecular epitaxy system were subjected to Co silicidation at two-step rapid thermal annealing. By using transmission line method (TLM) test structure, we extract the contact resistance noise in Co-silicide/SiGe interface. We find the contact noise increases with increasing Ge content in SiGe layer. When Ge content increases to 14%, the contact noise increases largely because many defects exist near the interface. The interface defect number can be reduced using a Si-cap upon SiGe layer, thus the noise magnitude reduces. The improved interface quality can also reduce the contact resistance.