MO-CVD growth of InGaAs using Me3Ga, AsMe3, AsH3 and Me3In or Et3In and analyses of adducts formed during the growth process

Abstract

High quality InGaAs films have been grown using the adduct Me₃In⋅AsMe₃ to block the room temperature reaction between Me₃In and AsH₃ and by using a cover piece to prevent the preferential evaporation of phosphorus from the InP substrate during the warm up. Infrared spectroscopy shows that Me₃Ga+AsMe₃ and Me₃Ga+AsH₃ form stable adducts at room temperature, Me₃In+AsMe₃ probably form a stable adduct, while Et₃In+AsMe₃ probably do not form a stable Lewis acid/base adduct. Poorer quality films are grown with Et₃In than with Me₃In because the AsMe₃ is unable to prevent by adduct formation the room temperature reaction between Et₃In and AsH₃. Pyrolysis studies show that the individual alkyls are stable to ∼ 400°C and mixtures are stable to ∼ 350°C. The problems associated with the lower vapor pressure of the adducts, adduct dissociation at room temperature and the growth temperature, and using an adduct as the starting material are discussed.