Formation and Characterization of Nickel Germanosilicide on Si1-xGex/Si/SiO2/Si

Abstract

TiN capped Ni/Si1-xGex/Si/SiO2/Si wafers are prepared to investigate the formation of nickel germanosilicides in the temperature range of 235oC ~ 400oC in 1 atm N2. The annealing was done in a stacked hotplate system for 10 min (wafer residence time in the heater chamber). The Ge content of 80 nm-thick Si1-xGex layers was varied between 15 and 30 at%. Sheet resistance of thin film stacks were measured using a four point probe as a function of annealing temperature and Ge content. Multiwavelength micro-Raman measurements and X-ray diffraction measurements were performed to investigate crystallographic phases and reaction mechanisms of resulting nickel germanosilicides. Excitation wavelength dependence of Raman measurements was found and optimum excitation wavelength was experimentally determined. Clear correlation among sheet resistance, X-ray diffraction and Raman spectra was found as a function of annealing temperature and Ge content. A combination of X-ray diffraction and multiwavelingth micro-Raman spectroscopy was found to be very promising as in-line monitoring techniques.