Schottky barrier formation of various metals on n-GaAs (100) by electrochemical deposition

Electrochemistry is used to deposit various metals (Pt, Pd, Ni, Co) on n-GaAs (100) surfaces to form Schottky barriers. For the first time very good rectifying characteristics, with an ideality factor n=1.04–1.08, are obtained, while the barrier heights match quite well those made under ultrahigh vacuum conditions. It is also shown that the possible disadvantages of this wet technique (oxidation, contamination,...), can be overcome provided that the conditions of deposition are carefully looked after: strong correlations between the electrical characteristics (studied by I–V and C–V measurements) and the interfacial morphology and composition (studied by Rutherford backscattering, nuclear reaction observation, and transmission electron microscopy) are evidenced when the electrodeposition conditions are varied for a given metal. The advantages of the method are also discussed within the framework of our results.