Scanning electron microscopy of long-wavelength laser structures

New possibilities of scanning electron microscopy, using secondary- and ref lected-electron signals, for determining the position of heteroboundaries i n long-wavelength laser structures are reported. The formation of the indic ated signals in structures of mid-infrared-range lasers of a new type based on type-II GaInAsSb/InGaAsSb heterostructures as well as in the convention al InAsSb/InAsSbP heterostructures is analyzed. The observed characteristic features of the formation of secondary- and reflected-electron signals in these structures as compared with the well-studied AlGaAs/GaAs structures a re explained. The results obtained are necessary for accurate determination of an important laser parameter - the position of the p-n junction. It is shown that it is best to use the reflected-electron signal. (C) 1998 Americ an Institute of Physics. [S1063-7826(98)00211-7].