Ideal GaAs Schottky contacts fabricated by in situ photoelectrochemical etching and electrodeposition

We have fabricated GaAs Schottky contacts with ideal diode characteristics by in situ photoelectrochemical etching of n-GaAs in electrolytic solutions containing metal ions just prior to electrodeposition (electroplating) of metal overlayers. Even by in situ etching, if not carried out properly, a minute residual oxide layer as thin as 1 nm would degrade the ideality factor (n value) of diodes. We here report that by using photocurrent transient measurements, it is possible to find the proper etching conditions that provide a surface free of residual oxide layers. By analyzing the Schottky barrier heights for the ideal diodes fabricated with four kinds of metals (Sn, Pb, Ni, Au), we have concluded that the value of the index of interface behavior S was around 0.1. (C) 1999 Scripta Technica, Electron Comm Jpn Pt 2, 82(5): 13-20, 1999.