Thermal dissociation of ditertiarybutylselenide and methylallylselenide and its impact on the growth of ZnSe by metalorganic vapour phase epitaxy

• Published in: Journal of crystal growth 1995-01, Vol.146 (1-4), p.580-586
• Main Authors: Kuhn, W.S., Helbing, R., Qu'Hen, B., Gorochov, O.
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Vapor phase epitaxy; growth from vapor phase
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/0022-0248(94)00542-7

The kinetic growth limitation in atmospheric pressure metalorganic vapour phase epitaxy (MOVPE) of ZnSe was investigated using the selenium precursors methylallylselenide (MASe) and ditertiarybutylselenide (DTBSe). The onset of mass transfer limited growth was found at ∼ 480 and ∼ 290°C for MASe and DTBSe, respectively. The activation energies for the kinetic growth were determined to be 11 kcal/mol for MASe and 14 kcal/mol for DTBSe. The decomposition of the alkyls was studied in an isothermal quartz tube by mass spectroscopy. For both precursors, an increase of the decomposition is found between 300–500°C. For DTBSe, the catalysis by a ZnSe surface lowers this temperature range to 140–260°C. Isobutane and isobutene were found as decomposition products of DTBSe. The intensities of these species depended on the catalytic or homogeneous nature of the pyrolysis. The co-pyrolysis of DTBSe with DMZn took place between 180–310°C, thus matching with the kinetic limitation observed in the growth.