Gas-Source Molecular Beam Epitaxial Growth of In1-xGaxP on GaAs Using Tertiarybutylphosphine

Abstract

A systematic study of growth was made for gas-source molecular beam epitaxial (GSMBE) growth of In1-xGaxP using tertiarybutylphosphine (TBP), in order to establish the conditions required to grow high-quality In1-xGaxP layers on GaAs(100) substrates. To clarify the effect of the P2 supply rate on growth, a special effort was made to increase the P2 supply by modifying the structure of the conventional cracking cell. The alloy composition and growth rate depended strongly on the type of cracking cell, growth temperature and TBP flow rate. The growth was group-III-limited at low growth temperatures, but became limited by thermal desorption of phosphorus at higher temperatures. The use of a high-efficiency cracking cell was found to be important for suppressing phosphorous evaporation and growing high-quality InGaP layers with controlled thickness and alloy compositions. Optimized growth led to an excellent photoluminescence (PL) property with a narrow peak width of 15.5 meV at 77 K and 38 meV at 300 K. These are comparable to the best data reported so far for InGaP layers grown by any method.