Revealing the Significance of Catalytic and Alkyl Exchange Reactions during GaAs and GaP Growth by Metal Organic Vapor Phase Epitaxy

Abstract

Tertiarybutylarsine (TBAs) and tertiarybutylphosphine (TBP) are getting more and more established as group V precursors for the growth of V/III semiconductors by metal organic vapor phase epitaxy (MOVPE). Due to this development, the thermal decomposition of these precursors was studied during the growth of GaAs and GaP utilizing the Ga precursors, trimethylgallium (TMGa), triethylgallium (TEGa), and tritertiarybutylgallium (TTBGa), in a horizontal AIXTRON AIX 200 GFR MOVPE system. The decomposition and reaction products were measured in line with a real-time Fourier transform quadrupole ion trap mass spectrometer from Carl Zeiss SMT GmbH. The decomposition temperatures and the related activation energies were determined for all the mentioned precursors under comparable reactor conditions. The decomposition curves suggest, on the one hand, a catalytic effect of the GaAs surface on the decomposition of TBAs. On the other hand, the decomposition products indicate alkyl exchange as a relevant step during the bimolecular decomposition of TBAs and TBP with the Ga precursors TMGa, TEGa, and TTBGa. The catalytic reaction reduces the decomposition temperature of TBAs and TBP by up to 200 °C. In addition, for the growth of GaAs with TBAs and TEGa and for the growth of GaP with TBP and TEGa, a significant decrease of the decomposition temperature with an increasing V/III ratio is observed. This behavior, which is related to an alkyl exchange reaction, gives insights into the low-temperature growth of GaAs and GaP and is converted into an effective V/III ratio. Finally, the growth of GaAs with TTBGa and TBAs is realized at 300 °C below the unimolecular decomposition temperature of TBAs, underlining the catalytic effect of the GaAs surface. Altering the growth surface with trimethylbismuth led to the prevention of the catalytic effect.

Metal Organic Vapor Phase Epitaxy in a Transmission Electron Microscope

“…It is reported that the formation of C 4 H 10 and •C 4 H 9 in the lower temperature regime is superseded by C 4 H 8 with increasing temperature. [ 16,17 ] Maßmeyer et al. observed the same decomposition products and suggested the reaction pathways of homolytic fission, intramolecular coupling, and β‐hydrogen elimination.…”

“…Extrapolating the PH 3 curve reveals that decomposition begins at a membrane temperature of (640 ± 20) °C, which aligns with the susceptor temperature of TBP decomposition in MOVPE reactors. [ 17 ] Consequently, the relationship between gas‐phase temperature and membrane temperature in the in situ TEM holder is comparable to that of gas‐phase temperature and susceptor temperature in conventional MOVPE reactor designs. With rising temperature, the amount of decomposed TBP increases continuously.…”

“…was performed in a horizontal MOVPE reactor combined with an Orbitrap mass spectrometer for various metal–organic precursors, including TBP and TMGa. [ 17 ] Their results also show a catalytic effect of TBP and TMGa on each other, reducing their decomposition temperatures. Furthermore, precursor decomposition behavior is sensitive to the choice of carrier gases, reactor geometry, reactive surfaces, total pressure, or precursor partial pressures.…”

“…Furthermore, precursor decomposition behavior is sensitive to the choice of carrier gases, reactor geometry, reactive surfaces, total pressure, or precursor partial pressures. [ 14–18 ]…”

Integration of Multijunction Absorbers and Catalysts for Efficient Solar‐Driven Artificial Leaf Structures: A Physical and Materials Science Perspective

“…For the latter challenge, in situ control during the preparation and operation is desired, for example, with benchmarking of in situ signals via interfacial characterization. [358,359] New III-V compounds involving nitrogen or boron for high-efficiency multijunction solar cell components may advance the portfolio of suitable materials. [360][361][362] To prepare III-V compounds, less hazardous, nongaseous, and more efficient precursor molecules should be employed such as tertiarybutylphosphine (TBP) instead of phosphine (PH 3 ), ditertiarybutylsilane (DTBSi) instead of silane (SiH 4 ), and tertiarybutylarsine (TBAs) instead of arsine (AsH 3 ).…”