The success of silicon as an electronic material is partially due to the characteristics of its native oxide, silion dioxide. In particular, silicon has become a dominant semiconductor due to the ability of its native oxide to act as a readily etched diffusion mask in the formation of planar diffused transistors. Gallium arsenide is rapidly becoming a popular electronic material and is used extensively for various optical and microwave devices. Spitzer et al in J. Electrochem. Soc., 121, No. 6, 820 (1974) have demonstrated that the native oxide of gallium arsenide can be used as a zinc diffusion mask. Unfortunately, the native oxide of gallium arsenide is heat sensitive. Upon exposure to heat, the oxide becomes inert to chemical dissolution. Attempts to remove the oxide usually damage the underlying crystal surface. While the oxide has been useful as an etching mask and for the surface passivation of lasers, the heat sensitivity limits its usefulness for high temperature manufacturing processes, such as diffusion steps wherein the temperature is typically in excess of 600.degree. C. The heat stabilized oxide gives gallium arsenide added versatility as a semiconductor, but some means for preventing the stabilization, would be desirable.