SILICON CROSS DOPING AND ITS EFFECT ON THE SI OR BE IMPLANTATION DOPING OF GALLIUM-ARSENIDE GROWN ON (100) SILICON BY METALORGANIC CHEMICAL VAPOR-DEPOSITION

A study of the cross doping of GaAs layers grown by a two-step metalorganic chemical vapor deposition on Si substrates is reported. All as-grown, unintentionally doped layers of GaAs were n-type, and the carrier profiles tracked the Si atomic profiles. Furnace annealing at 850-degrees-C for 30 min in an arsine overpressure, which is used to improve the crystalline quality of the GaAs near the heterointerface, caused additional Si to diffuse into the GaAs layer. Comparison of the Si concentration at the interface with the carrier concentration suggested the presence of compensating acceptors. Resonance Raman scattering by the Si(As) local vibrational mode near the interface shows that a fraction of the Si atoms are localized at the As sites. The furnace annealing increased the Si concentration in the 1.7-1.8-mu-m thick initially grown GaAs layer. This, in turn, influenced the electrical profiles created with Si or Be implantation on a 2.3-mu-m thick GaAs layer.