This paper presents technological conditions to grow large area of native oxides on AlGaAs epilayers, to be used in laser diodes technology.Experimental results from SEM and EDS measurements reveals the presence of two native oxides forms : GaAsO and AlGaAsO on a large surface of lateral growth twice than in literature. the proposed oxides structures are Ga(0.5)As(0.5)O and Al(0.1)Ga(0.4)As(0.5)O(2). These oxide forms have dielectric behaviour on