Mass-spectrometric monitoring of the thermally induced decomposition of trimethylgallium, tris(tert-butyl)gallium, and triethylantimony at low pressure conditions.

The thermal decomposition of trimethylgallium (GaMe(3)), tris(tert-butyl)gallium (Ga(t)Bu(3)) and triethylantimony (SbEt(3)) was investigated in a tubular hot-wall reactor coupled with a molecular-beam sampling mass spectrometer, and decomposition mechanisms were proposed. The obtained results confirm the predominance of the surface reactions and reveal that the radical decomposition path of Ga(t)Bu(3) and SbEt(3), responsible for the formation of butane and ethane respectively, is restricted to a narrow temperature range in contrast to the molecular route that is responsible for the formation of the corresponding alkenes. GaMe(3) decomposes above 480 degrees C, forming essentially methane and also ethane to a lesser extent, whereas Ga(t)Bu(3) decomposes starting 260 degrees C to form predominantly i-butane and i-butene as major species.