Macroscopic and nanometer scale stress measurement of Ni(Pt)Si silicide: Impact of thermal treatments ranging from millisecond to several hours

Abstract

The authors have measured and compared the stress in nickel silicide full sheet layers prepared with added platinum on (001) p-type Si wafers by using either a rapid thermal anneal (RTA) at 390 °C or a millisecond submelt laser dynamic scanning anneal (DSA) at 800 °C. The room temperature tensile stress of the silicide annealed with DSA is 1.65 GPa, whereas that of the silicide annealed with RTA at 390 °C is 800 MPa. Our analysis confirms that the origin of the stress lies in thermal expansion factors. Despite some small variations, the stress remains highly tensile in both layers after a 1 h post-treatment at 400 °C, with values of 1.4 GPa and 850 MPa for the DSA and RTA samples, respectively. The authors also performed strain measurements with dark field electron holography in the source drain region of 28 nm field complementary metal oxide semiconductor field effect transistors, under the silicide dot. They then determined the stress inside the silicide by combining the strain measurement with finite element mechanical simulations; values of 1.5 GPa and 600 MPa were found at the nanometer scale for the DSA and RTA samples, respectively, which are consistent with the macroscopic observations.