AlxGa1 - xSb layers on GaSb(0 0 1) have been grown by molecular beam epitax
y (MBE) and characterised by high-resolution X-ray diffraction (HRXRD) and
secondary ion mass spectrometry (SIMS) measurements. The antimonide layers
inevitably contain residual As amounting to 0.5 mol%. This cannot be avoide
d when growing the films in a MBE apparatus previously used for GaAs growth
, at least for the applied growth temperature of 470 degrees C. Segregation
processes of Ga from the GaSb buffer layer and Al from the heteroepitaxial
layer into the layers above are detected by SIMS. Since monomeric Sb forms
metallic films on the sample surface, the exposure to a monomeric Sb flux
below 370 degrees C should be avoided in order to obtain a clean surface. T
he composition of the 150 nm thick quaternary AlxGa1 - xAsySb1 - y layers w
as determined with high precision. (C) 1999 Elsevier Science B.V. All right
s reserved.