IMPURITY CHARACTERIZATION OF SI(1-X)GE(X) CIRCUIT STRUCTURES WITH THEUSE OF NEUTRON-ACTIVATION ANALYSIS

The recent use is reported of neutron activation analysis to determine the elemental content of silicon-germanium layers that were epitaxial ly grown on antimony-doped single crystal silicon substrates. The subs trates formed part of gold-contact Schottky diode circuits. Gamma rays from the activation products Ge-75 and Ge-77 were used, and the usefu lness was demonstrated of the gallium K(alpha) X ray, emitted in the e lectron capture decay of Ge-71, to identify and quantify the germanium in our samples. Minor components of the silicon matrix and their bulk atomic concentrations for specimens having masses of approximately 56 mg were germanium (4 ppm), gold (2 ppm), and antimony (32 ppm). Estim ates for the germanium atom fraction x, in the layers, in the range of 6 to 8%, were obtained for the samples studied.