Ligand exchange reactions in InGaAs metalorganic vapor-phase epitaxy

Mixed alkyl exchange and exploitable surface interactions in InGaN by NH3-based metal organic molecular beam epitaxy

“…Furthermore, this suggests that in NH 3 -based growth, it is critical to be near T s $540 1C [12] to achieve both as much active N as possible and to reduce In/In-methyl surface coverage. Furthermore, the high surface In/In-methyl coverage helps facilitate the formation and desorption of Ga-alkyl species by rapid alkyl exchange (ethyl with methyl) in a similar manner to that previously observed with the use of mixed alkyl precursors [15][16][17][18]. As physisorbed In and In-methyl species ride on the surface, methyl ligands strongly bond to excess Ga atoms made available via facile b-elimination [24,25].…”

“…These species are not suspected as byproducts of RGA ionization, as separate measurements of TEGa cracking in the present reactor show different species at m/e ¼ 85 and 87, 114 and 116, and 157 and 159 that are not observed during In x Ga 1Àx N growth. Moreover, rapid alkyl exchange has been observed in InGaAs with TMIn and TEGa [15,16], AlGaSb with TIBAl and TEGa [17], and IR laser pyrolysis of gas-phase TEGa and TMGa [18]. In these cases, mixed alkyl precursors are employed-causing any weakly bonded alkyls (typically ethyl groups) to be rapidly replaced by strongly bonded, less reactive alkyls (typically methyl groups).…”

A comparison of TMG with TEG for the growth of InxGa1−xAs

“…The pyrolysis temperature of TMG (489°C) is much higher than TEG (326°C). 7,10 Recently, in an important piece of work, 15 it was shown that there are ligand exchange reactions in the feed lines to the reactor, and presumably in the gas-phase above the growing wafers. 13 At the surface, the decomposition of TMG and TEG are different, 11 TMG decomposes to produce CH 4 while TEG decomposes to produce C 2 H 4 .…”

Metal Organic Vapor Phase Epitaxy Chemical Kinetics

“…In the case of group 13 sources, the exchange of ligands within the gas phase has been previously noted [111][112][113]. The growth of the film is not generally the superposition of the individual reactions.…”