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 tertia rybutylphosphine (TBP) and tertiarybutylarsine (TBA) has been investig ated. Measurement of the specific heat of TBP and TEA allows the absol ute delivery rates of reactants to be controlled accurately to achieve a wide range of V/III ratios. The analysis of the quaternary composit ion shows that the incorporation of group III elements is determined s olely by their delivery rate, independent of the group V composition. Meanwhile, the group V sublattice composition at typical growth temper atures is determined by a single parameter - the TBP/III ratio. The in corporation efficiency of TEA relative to TBP increases and then satur ates as the TBP/III ratio increases. A model is proposed based on the balance between enhancement of the decomposition of TEA in the presenc e of t-butyl or PHn (n = 1 or 2) radicals and its suppression by the p resence of group III radicals. (C) 1998 Elsevier Science B.V. All righ ts reserved.