Ge quantification of high Ge content relaxed buffer layers by RBS and SIMS

The combined use of Rutherford backscattering spectrometry and secondary ion mass spectroscopy allowed the complete characterization of relaxed graded SiGe buffer layers grown by low-energy plasma-enhanced chemical vapor deposition, in the full range of Ge composition. The Ge contents for the top constant composition layers were obtained by Rutherford backscattering spectrometry. Matrix effects were studied using monoatomic and biatomic ions as well as low and high energy O2+ and Cs+ primary beam ions. We show that matrix effects are suppressed when an O2+ primary beam ion source is used at 3 keV, and when detecting 30Si+ and 70Ge+ secondary ions for Ge contents <0.47. For higher Ge contents a better compromise is achieved with Cs+ bombardment at 14.5 keV when detecting 74Ge76Ge- secondary ions. By using these experimental results, a set of p-MODFET structures was characterized using Cs+ bombardment at 14.5 keV. © 2004 Elsevier B.V. All rights reserved.