Comparison of the As compounds tertiarybutylarsine and monoethylarsine

Abstract

We have studied the use of tertiarybutylarsine (TBAs) and monoethylarsine (MEAs) for LP-MOVPE (low pressure metalorganic vapor phase epitaxy). From vapor pressure measurements before and after growth, we conclude that TBAs decomposes into AsH 3 and isobutene at room temperature, while MEAs appears to be stable. In the case of a total reactor pressure p tot = 100 hPa, we demonstrate that the use of a saturated group III precursor dimethylaminopropyl-galla-cyclohexane (APGH) in combination with organoarsenics like TBAs suppresses undesired parasitic reactions which are detected if TMG is used. At conditions ( p tot = 20 hPa, v = 100 cm/s), where unwanted side reactions between organoarsenics and TMG are not observed, we compared the growth habit of the As sources TBAs and MEAs in combination with the standard Ga compound TMG. A higher V/III ratio is needed in the case of MEAs to achieve the same layer quality (surface morphology, C contamination) of layers grown with TBAs. The results indicate that both As compounds are suitable replacements of AsH 3 for epitaxial growth of GaAs in LP-MOVPE.