Aerosol particles from metalorganic vapor phase epitaxy bubblers

Abstract

We report on aerosol particles formed by bubbling a carrier gas through bubblers in metalorganic vapor phase epitaxy (MOVPE). A triethylgallium bubbler was investigated in a MOVPE set-up regarding the generation of aerosol. We measured particle number concentrations with an ultrafine condensation particle counter, which can detect submicrometer aerosol particles larger than 3 nm in diameter. We found that a standard triethylgallium bubbler used in a conventional way produces aerosol particles. The number of particles is a function of the carrier gas flow through the bubbler and correlates with the number of bubbles. The aerosol size distributions were analyzed with a differential mobility particle sizer and found to range from 10 to 600 nm, with maxima between 150 and 200 nm. Size distribution as well as total number of aerosol particles depend on evaporation processes during transport in undersaturated gas flows. While the number of particles reaching the reactor is not negligible, the precursor is predominantly transported as gas molecules. Particles can in principle, though, reach the substrate and create defects on the surface.