Nanometer-scale strain measurements in semiconductors: An innovative approach using the plasmon peak in electron energy loss spectra

摘要

We present an innovative technique for quantitative measurement of strain in semiconductor materials with high spatial resolution. The plasmon loss peak, seen in electron energy-loss spectra, has been considered following the Drude-Lorentz model, and we find that plasmon energy is extremely sensitive to lattice parameter. We have tested this model using a heterostructure of In_(0.2)Ga_(0.8)As and AlAs layers in GaAs. The experimental data are in excellent agreement with the model. We estimate that strains smaller than 0.036% can be detected, corresponding to a change of x = 0.005 in In_xGa_(1-x)As, at a spatial resolution better than 2.8 nm.