The composition dependence of GaInAs grown by organometallic epitaxy

Abstract

In this paper we describe a systematic study of the parameters affecting the composition of Ga 1− x In x As grown from trimethylgallium, triethylindium and arsine. Reactor pressure, reactant partial pressures, substrate temperature ans the susceptor slope were varied to determine the depletion of indium species as a function of these parameters. A two-step model is proposed, with the second step involving two parallel paths. In the first step, the triethylindium reacts with the arsine to form an adduct, which is transported to the hot zone of the reactor. There it dissociates to liberate triethylindium. Simultaneously, however, some adduct molecules decompose via alkyl elimination in the gass phase resulting in a loss of indium to the growth process. A bimolecular alkyl elimination reaction is proposed, consistent with the change in composition with reactor parameters. Conditions for compositionally uniform growth were determined, and uniform composition (within ±0.005) achieved over the entire 2.5 cm×1.5 cm face of the susceptor in a 50 mm ID reaction chamber.