Solid-state reaction in Pd/ZnSe thin film contacts

We report on solid‐state reactions in Pd thin film contacts on ZnSe at temperatures below 500 °C. We found that a solid‐state reaction was initiated at the Pd/ZnSe interface by thermal annealing at 200 °C. A tetragonal ternary phase, Pd5+xZnSe, consisting of highly oriented grains was formed as a result of this reaction. This phase is found to be stable up to an annealing temperature of 400 °C. The crystallography and morphology of this ternary Pd–ZnSe phase was studied by x‐ray diffraction and transmission electron microscopy and has similarities to the analogous ternary Pd–GaAs phase formed in the Pd/GaAs contact structure. The Pd/ZnSe interface is found to be thermally more stable than the corresponding Pd/GaAs and Pd/Si structures. Comparisons are made between the systematics of Pd/semiconductor interfacial phenomena on the three semiconductors.