A strained layer of Si1−xGex(As)/Si has been grown by molecular beam epitaxy (MBE) with the As dopant introduced by 1 keV ion implantation during growth. Analysis of the layer was made using secondary‐ion mass spectrometry (SIMS), Rutherford backscattering (RBS), and proton‐induced x‐ray emission (PIXE)/channeling, using 2 MeV H+ions. The layer thickness (∼1.4 &mgr;m) and composition (x∼0.015;nAs∼6×1018cm−3) measurements by SIMS, RBS, and PIXE were in agreement. RBS, PIXE/channeling showed that the crystalline quality of the strained layer was equivalent to that of the Si substrate. The substitutional fraction (∼0.75) of the As dopant was determined by PIXE/channeling.