’’Surface exchange’’ doping of MBE GaAs from S and Se ’’captive sources’’

Lead was not detectably incorporated in GaAs during MBE growth above 480 °C, and films grown under massive fluxes of lead show no degradation of material properties. This effect was utilized in the ’’surface exchange’’ n-type doping of GaAs with S and Se using PbS and PbSe as captive sources. The processes were shown to be efficient and able to produce relatively uncompensated material. 150-Å-wide spikes in doping could be easily produced, indicating a very low surface rate limitation to incorporation.