SIMS profile analyses for Ge-, Co- and Fe-doped InP substrates used in epitaxial growth

Cockayne and co-workers have shown recently that germainum (Ge) or cobalt (Co) doping of liquid-encapsulation Czochralski (LEC) grown indium phosphide (InP) single crystals produces potentially useful properties in the application of this III-V compound as a substrate material for the manufacture of a number of electronic devices. An important factor in determining applications for these materials is a knowledge of the extent to which cobalt and germanium migrate into epitaxial layers grown on to substrates doped with these elements. Here, the authors report the results of secondary-ion mass spectrometric (SIMS) analysis of undoped layers grown on to such substrates by either vapour phase epitaxy (VPE) or molecular beam epitaxy (MBE). Comparison is made with layers grown similarly on the Fe-doped substrates.