This paper reports the first use of an amorphous native oxide on gallium arsenide to mask against zinc diffusion. Anodic oxides were grown at low temperature (≤100°C), and stripes were defined in this oxide using standard photolithographic processing. These samples were diffused, after an appropriate annealing cycle, in a closed system using a zinc source
(
Zn
3
As
2
+
GaAs
)
at 612°C for times up to 2 hr. Diffusion depths were measured using a lap and stain procedure, and the results showed the oxide to be effective as a zinc barrier. Furthermore, no anomalous lateral underdiffusion was observed indicative of a high integrity interface between the oxide and semiconductor.