Monitoring of HyGaNx and Ga in OMCVD of GaN, using molecular beam quadrupole and REMPI-TOF mass spectrometry

A new route in organometallic chemical vapour deposition (OMCVD) of GaN layers is the single-source precursor method. Molecular beam sampling using quadrupole mass spectrometry and resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOF-MS) has been used to show that gallium atoms and gallium–nitrogen compounds, like HGaNx (x=2–6) and GaNx (x=2–6), appear in the boundary layer of a sapphire substrate during thermal decomposition of (N3)2Ga[CH2CH2CH2N(CH3)2] in the temperature range 400–1000 K. The temperature dependence of the species is shown to be directly correlated with the growth rate of GaN layers.