Zinc Diffusion into Gallium Phosphide under High and Low Phosphorus Overpressure

The acceptor zinc has been diffused into n‐type single crystal gallium phosphide at temperatures between 700° and 1000°C from diffusion sources which lie in two different regions of the Ga‐P‐Zn phase diagram. One source (pure zinc) provides low phosphorus overpressure and leads to p‐n junctions which are distinctly nonplanar. The other (zinc plus excess phosphorus) provides high phosphorus overpressure and leads to smaller diffusion coefficients and considerably more planar p‐n junctions. These effects are consistent with the interstitial‐substitutional model for diffusion of zinc in . With either source, diffusion induced dislocations are formed throughout the diffused layer after an incubation time. The p‐n junction depth corresponding to the first appearance of the induced dislocations is found to be greater when the high phosphorus pressure source is used.