The chemical processes which occurred during the diffusion of Zn from spun-on SiO2 films and into wafer samples were investigated. It was found that, at 600C, only about 45% of the film was changed to SiO2 glass. At 700C, Zn silicates began to form. When the Zn was in this form, it was much less able to diffuse into the GaAs.

E.Nowak, G.Kühn, B.Schumann, R.Hesse, H.Sobotta: Crystal Research and Technology, 1992, 27[4], 503-8