Carbon incorporation mechanism in atomic layer epitaxy of GaAs and AlGaAs

By an in-situ surface photo-absorption study of the ALE process and carbon atomic layer doping, an other than the so far proposed carbon incorporation mechanism via formation of a CH2 bridge bond has been found, i.e. carbon incorporation via an exchange reaction between dissociated CH3 radicals from TMG and As atoms of the surface onto which TMG is deposited. We also propose a method for reducing the carbon incorporation by thermal desorption of the CH3 groups.