MODULATED-BEAM MASS-SPECTROMETRY STUDIES OF THE MOMBE GROWTH OF (100) GAAS AND IN0.1GA0.9AS

Modulated-beam mass spectrometry has been used for the first time to study the MOMBE growth of (100) GaAs and In0.1Ga0.9As using appropriate combinations of triethyl gallium, triethyl indium and arsenic tetramer sources. The GaAs MOMBE growth process has been monitored as a systematic function of substrate temperature, V : III flux-ratio and growth rate. These experiments indicate that rapid thermal decomposition of triethyl gallium takes place with increasing substrate temperature (80-350°C) to generate an increasing concentration of desorbing diethyl gallium. For substrate temperatures greater than 350°C, progressively increasing thermal decomposition of the diethyl gallium occurs at the substrate surface, and GaAs growth commences. Three specific subsequent growth regions are then identified as a function of increasing substrate temperature. The data obtained as a function of the different growth variables is then used to explain previously reported GaAs MOMBE growth rate results, and implications for the existing models of MOMBE growth processes are described. Finally, preliminary modulated-beam mass spectrometry data obtained during the MOMBE growth of In0.1Ga0.9As is described and correlated with previously reported InxGa1 - xAs MOMBE growth studies. © 1990.