Composition control of InGaAsP in metalorganic chemical vapor deposition using tertiarybutylphosphine and tertiarybutylarsine

The incorporation of source elements in the low-pressure metalorganic chemical vapor deposition of InGaAsP quaternary compounds using tertiarybutylphosphine (TBP) and tertiarybutylarsine (TBA) has been investigated. Measurement of the specific heat of TBP and TEA allows the absolute delivery rates of reactants to be controlled accurately to achieve a wide range of V/III ratios. The analysis of the quaternary composition shows that the incorporation of group III elements is determined solely by their delivery rate, independent of the group V composition. Meanwhile, the group V sublattice composition at typical growth temperatures is determined by a single parameter - the TBP/III ratio. The incorporation efficiency of TEA relative to TBP increases and then saturates as the TBP/III ratio increases. A model is proposed based on the balance between enhancement of the decomposition of TEA in the presence of t-butyl or PHn (n = 1 or 2) radicals and its suppression by the presence of group III radicals. (C) 1998 Elsevier Science B.V. All rights reserved.