Characterization of SiGe Films for use as a National Institute of Standards and Technology (NIST) Microanalysis Reference material (RM 8905)
Ryna B. Marinenko, Shirley Turner, David S. Simons, Savelas A. Rabb, Rolf L. Zeisler, Lee L. Yu, Dale E. Newbury, Rick L. Paul, Nicholas W. Ritchie, Stefan D. Leigh, Michael R. Winchester, Lee J. Richter, Douglas C. Meier, Keana C. Scott, D Klinedinst, John A. Small
Bulk SiGe wafers cut from single-crystal boules and two SiGe thick films (4 m and 5 m thick) on Si wafers were evaluated with the electron probe microanalyzer for the extent of heterogeneity and composition for use as reference materials needed by the microelectronics industry in the characterization of SiGe thin films on Si. Alloys with nominal compositions of Si0.86Ge0.14 and Si0.935Ge0.065 and two thick films with nominal compositions of Si0.90Ge0.10 and Si0.75Ge0.25 on Si were rigorously tested with wavelength dispersive spectrometers (WDS) using multiple point, multiple sample, and duplicate data acquisitions to determine the micro- and macroheterogeneity. The Si0.86Ge0.14 alloy and the two films are good microanalysis reference materials with an overall expanded heterogeneity uncertainty of 1.1 % relative or less for Ge. Instrumental neutron activation analysis (INAA) and inductively coupled plasma-optical emission spectrometry (ICP-OES) were used to determine the Ge composition in the Si0.86Ge0.14 alloy. The results are 30.228 % mass fraction Ge with an expanded uncertainty of the mean of 0.195 % mass fraction. WDS was used for the quantification of the thick films using both the Si0.86Ge0.14 alloy and pure element wafers as reference materials. The concentration for Ge was determined to be 22.80 % mass fraction with an expanded uncertainty of the mean of 0.120 % mass fraction for the Si0.90Ge0.10 wafer and 43.66 % mass fraction for the Si0.75Ge0.25 wafer with an expanded uncertainty of the mean of 0.246 % mass fraction. The two thick SiGe films will be issued as NIST reference materials (RM 8905).