OMVPE of InAlAs Using Alternative Al and As Precursors

Abstract

ABSTRACTAlternate aluminum and arsenic precursors were investigated for InAlAs grown by organometallic vapor phase epitaxy (OMVPE). The quality of the InAlAs growths was investigated by secondary-ion mass spectrometry (SIMS) to measure impurity concentrations. Trends are extracted from SIMS measurements for each precursor as a function of V/III ratio and growth temperature. Two arsenic precursors, arsine and tertiarybutylarsine (TBAs), were chosen to compare InAlAs growth quality. The impurity concentrations measured by SIMS decrease as the V/III ratio increases, for both arsine and TBAs growths. Impurities also decrease as growth temperature increases. Two aluminum precursors, trimethylaluminum (TMAl) and tritertiarybutylaluminum (TTBAl), were used to compare the effect of alumimum precursor on carbon and oxygen impurity levels. TMAl is widely studied in literature, though TTBAl is less common. This study represents the first report using the TTBAl precursor for InAlAs growth. Each aluminum source is used in conjunction with each aforementioned arsenic precursor in order to compare all possible precursor combinations. TMAl growths demonstrated decreasing impurities with increasing V/III ratio. TTBAl growths did not exhibit such a dependence, impurity concentrations remained virtually constant regardless of V/III ratio.