Strain mapping at the interface of InP/In _x Ga_1-x As/InP as measured by the scanning transmission electron microscope-moiré fringe method

Abstract

Recently, the scanning transmission electron microscope-moiré fringe (SMF) method has attracted much interest because of its precise estimation of the local strain distribution of strained semiconducting devices. In this study, by SMF method, we found that the strain was not uniformly distributed in the InxGa1-xAs layer when it was sandwiched between two InP layers. The most notable point is that the In0.53Ga0.47As layer showed compressive strain at the interface with the InP buffer layer, and showed tensile strain at the interface with InP cap layer even though both InP and In0.53Ga0.47As had the same lattice constant.

Moiré Fringe Method via Scanning Transmission Electron Microscopy

“…[ 71,72 ] It should be noted that a higher accuracy of strain quantification was achieved by averaging over two fringes at the cost of some loss in spatial resolution. [ 71 ] Inspired by Kim's work on semiconductors, more work using STEM‐MF was carried out to evaluate strain distribution, including Ge/Si interface, [ 73 ] compositionally step‐graded SiGe/Si interface, [ 74 ] In 0.6 Ga 0.4 As/In 0.56 Al 0.44 As superlattice structure for quantum cascade lasers, [ 75 ] InP/In x Ga 1− x As/InP interface, [ 76 ] and fin field‐effect transistor. [ 77,78 ]…”