CCl4 doping of GaN grown by metalorganic molecular beam epitaxy

Hole concentrations up to 10¹⁷ cm^-3 are achieved in GaN doped with C from a CCl4 source during metalorganic molecular beam epitaxy at 700 °C. The hole mobility under these conditions is 103 cm² V^-1 s^-1 at 300 K. The deposition rate of the GaN is reduced by addition of CCl4 to the growth chemistry even at low flow rates and net etching is observed for a halocarbon flow above 1.1 sccm under our conditions. Annealing up to 800 °C did not increase the hole concentration indicating that residual hydrogen passivation of the acceptors is not significant when employing a He carrier gas for transporting the group III metalorganic precursor (triethylgallium). © 1995 American Institute of Physics.