A mass spectrometry study of the gas pyrolysis of PH3 and a PH3/Si2H6 mixture

Abstract The thermal dissociation of phosphine and of a phosphine—disilane gas mixture as a function of temperature has been studied in an impinging jet type LPCVD reactor. In order to measure the influence of homogeneous gas phase reactions, two configurations (cold and hot wall) were used. A quadrupole mass spectrometer (QMS) coupled with the reactor using a sampling system near the substrate surface was used to follow the gas phase composition. PH 3 begins to decompose at 550°C. Formation of the phosphorus dimer (P 2 ) and tetramer (P 4 ) is demonstrated; P 4 is the main product. When Si 2 H 6 is added to this gaseous mixture, formation of monosilylphosphine SiPH 5 is observed.