Formation of Titanium Silicide on Ion-Implanted Silicon

Abstract

AbstractThe formation of TiSi2 was compared over samples implanted with arsenic and BF2 at different doses and annealed at different temperatures and lengths of time in a rapid thermal process. Measurements were done to determine the composition and thickness of the suicide formed. The composition was determined from Auger electron spectroscopy, Rutherford backscattering spectroscopy, and transmission electron microscopy. The phase formation of the suicide was characterized by X-ray diffraction. Dopant redistribution was studied using secondary ion mass spectroscopy. Comparing the results of the different implant doses we found that the amount of suicide formed over heavily doped Si at formation temperatures of 600°C to 650°C was reduced compared to undoped Si. At formation temperatures above 750°C the implanted dose and species did not significantly affect the amount of suicide formation. Above 750°C the TiSi2 structure was found to be the C54 phase. Arsenic was found to diffuse into the Ti suicide layer in a diffusion controlled process. Boron was found to accumulate at the Ti suicide interfaces both with the substrate and with the surface TixOyNz layer.