The role of stoichiometry in low temperature grown GaAs for MESFET structures

A detailed investigation of the growth conditions, including growth dynamics, has established that the non-stoichiometry of LT GaAs is not an intrinsic property but a perfectly controllable one leading to the possibility of growth of Stoichiometric Low temperature (SLT) GaAs. Epitaxial layers of both LT and SLT GaAs layers were grown and assessed as to their suitability as buffer layers in conventional MESFET structures. Both the mobility and charge density in the channel are shown to be strongly affected by the underlying buffer layer. Because of the control afforded in the growth of this structure using stoichiometric beams, a MESFET structure was entirely grown at the low growth temperature of 350/spl deg/C and yet still retained high electrical and optical properties.