Influence of arsenic doping on the electrical properties of GaN epitaxial layers grown by MOCVD

The influence of arsenic doping on the electrical properties of GaN films grown on sapphire substrates by metalorganic chemical vapor deposition has been investigated using temperature dependent Hall effect and deep-level transient spectroscopy measurements. With an increase in arsine flow rate from 1.5 to 100 sccm, the carrier concentration increases from 8.6/spl times/10/sup 16/ to 7.5/spl times/10/sup 17/ cm/sup -3/ while the mobility ranges from 250 to 400 cm/sup 2//Vs. Two deep electron trap levels were observed at around 0.22 and 0.60 eV from the undoped GaN sample, whereas the deep level at around 0.22 eV was not observed in the As-doped samples.