Electrochemical reduction vs. vapour deposition for n-GaAs/Cu Schottky-barrier formation: a comparative study

Abstract

Copper has been deposited electrochemically upon (100) n-GaAs at different electrode potentials. The height of the Schottky barriers thus formed was measured and compared to that of n-GaAs/Cu junctions prepared by vapour deposition. Whereas, initially, the barrier height, Φ_B, was about the same for both types of junctions, Φ_B was seen to increase with time when the electrochemically formed barriers were left in air. The morphology of the copper phase was studied by atomic force microscopy (AFM), revealing a relationship between the roughness of the copper layer and the occurrence of the ageing effect. From these data, an interpretation for the latter was proposed, based upon the growth of an interfacial oxide layer.