GaAs Schottky Diodes with Ideality Factor of Unity Fabricated by In Situ Photoelectrochemical Process

Schottky contacts to n-GaAs have been fabricated by means of a photoelectrochemical process in which in situ anodic etching of the substrate surface was performed in the same electrolytic solution as for electroplating of metals (Ni, Au, Sn and Pb). Measurement of the cyclic voltammogram was helpful in determining the applied voltages for in situ etching as well as metal deposition, and thus in fabricating good Schottky contacts reproducibly. The ideality factor (n value) of the fabricated diodes was unity for the substrate with an electron density of 2×1016 cm-3. The values of Schottky barrier heights determined by means of the I-V and C-V methods were in close agreement, and the chemical trend was clearly observed.